fune/dom/base/nsFocusManager.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/dom/TabParent.h"

#include "nsFocusManager.h"

#include "ChildIterator.h"
#include "nsIInterfaceRequestorUtils.h"
#include "nsGkAtoms.h"
#include "nsGlobalWindow.h"
#include "nsContentUtils.h"
#include "nsIContentParent.h"
#include "nsPIDOMWindow.h"
#include "nsIDOMChromeWindow.h"
#include "nsIHTMLDocument.h"
#include "nsIDocShell.h"
#include "nsIDocShellTreeOwner.h"
#include "nsIFormControl.h"
#include "nsLayoutUtils.h"
#include "nsIPresShell.h"
#include "nsFrameTraversal.h"
#include "nsIWebNavigation.h"
#include "nsCaret.h"
#include "nsIBaseWindow.h"
#include "nsIXULWindow.h"
#include "nsViewManager.h"
#include "nsFrameSelection.h"
#include "mozilla/dom/Document.h"
#include "mozilla/dom/Selection.h"
#include "nsXULPopupManager.h"
#include "nsMenuPopupFrame.h"
#include "nsIScriptObjectPrincipal.h"
#include "nsIPrincipal.h"
#include "nsIObserverService.h"
#include "nsIObjectFrame.h"
#include "nsBindingManager.h"
#include "nsStyleCoord.h"
#include "TabChild.h"
#include "nsFrameLoader.h"
#include "nsNumberControlFrame.h"
#include "nsNetUtil.h"
#include "nsRange.h"

#include "mozilla/AccessibleCaretEventHub.h"
#include "mozilla/ContentEvents.h"
#include "mozilla/dom/Element.h"
#include "mozilla/dom/HTMLImageElement.h"
#include "mozilla/dom/HTMLInputElement.h"
#include "mozilla/dom/HTMLSlotElement.h"
#include "mozilla/dom/Text.h"
#include "mozilla/EventDispatcher.h"
#include "mozilla/EventStateManager.h"
#include "mozilla/EventStates.h"
#include "mozilla/HTMLEditor.h"
#include "mozilla/IMEStateManager.h"
#include "mozilla/LookAndFeel.h"
#include "mozilla/Preferences.h"
#include "mozilla/Services.h"
#include "mozilla/Unused.h"
#include <algorithm>

#ifdef MOZ_XUL
#  include "nsIDOMXULMenuListElement.h"
#endif

#ifdef ACCESSIBILITY
#  include "nsAccessibilityService.h"
#endif

#ifndef XP_MACOSX
#  include "nsIScriptError.h"
#endif

using namespace mozilla;
using namespace mozilla::dom;
using namespace mozilla::widget;

// Two types of focus pr logging are available:
//   'Focus' for normal focus manager calls
//   'FocusNavigation' for tab and document navigation
LazyLogModule gFocusLog("Focus");
LazyLogModule gFocusNavigationLog("FocusNavigation");

#define LOGFOCUS(args) MOZ_LOG(gFocusLog, mozilla::LogLevel::Debug, args)
#define LOGFOCUSNAVIGATION(args) \
  MOZ_LOG(gFocusNavigationLog, mozilla::LogLevel::Debug, args)

#define LOGTAG(log, format, content)                      \
  if (MOZ_LOG_TEST(log, LogLevel::Debug)) {               \
    nsAutoCString tag(NS_LITERAL_CSTRING("(none)"));      \
    if (content) {                                        \
      content->NodeInfo()->NameAtom()->ToUTF8String(tag); \
    }                                                     \
    MOZ_LOG(log, LogLevel::Debug, (format, tag.get()));   \
  }

#define LOGCONTENT(format, content) LOGTAG(gFocusLog, format, content)
#define LOGCONTENTNAVIGATION(format, content) \
  LOGTAG(gFocusNavigationLog, format, content)

struct nsDelayedBlurOrFocusEvent {
  nsDelayedBlurOrFocusEvent(EventMessage aEventMessage,
                            nsIPresShell* aPresShell, Document* aDocument,
                            EventTarget* aTarget, EventTarget* aRelatedTarget)
      : mPresShell(aPresShell),
        mDocument(aDocument),
        mTarget(aTarget),
        mEventMessage(aEventMessage),
        mRelatedTarget(aRelatedTarget) {}

  nsDelayedBlurOrFocusEvent(const nsDelayedBlurOrFocusEvent& aOther)
      : mPresShell(aOther.mPresShell),
        mDocument(aOther.mDocument),
        mTarget(aOther.mTarget),
        mEventMessage(aOther.mEventMessage) {}

  nsCOMPtr<nsIPresShell> mPresShell;
  nsCOMPtr<Document> mDocument;
  nsCOMPtr<EventTarget> mTarget;
  EventMessage mEventMessage;
  nsCOMPtr<EventTarget> mRelatedTarget;
};

inline void ImplCycleCollectionUnlink(nsDelayedBlurOrFocusEvent& aField) {
  aField.mPresShell = nullptr;
  aField.mDocument = nullptr;
  aField.mTarget = nullptr;
  aField.mRelatedTarget = nullptr;
}

inline void ImplCycleCollectionTraverse(
    nsCycleCollectionTraversalCallback& aCallback,
    nsDelayedBlurOrFocusEvent& aField, const char* aName, uint32_t aFlags = 0) {
  CycleCollectionNoteChild(aCallback, aField.mPresShell.get(), aName, aFlags);
  CycleCollectionNoteChild(aCallback, aField.mDocument.get(), aName, aFlags);
  CycleCollectionNoteChild(aCallback, aField.mTarget.get(), aName, aFlags);
  CycleCollectionNoteChild(aCallback, aField.mRelatedTarget.get(), aName,
                           aFlags);
}

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsFocusManager)
  NS_INTERFACE_MAP_ENTRY(nsIFocusManager)
  NS_INTERFACE_MAP_ENTRY(nsIObserver)
  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIFocusManager)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(nsFocusManager)
NS_IMPL_CYCLE_COLLECTING_RELEASE(nsFocusManager)

NS_IMPL_CYCLE_COLLECTION(nsFocusManager, mActiveWindow, mFocusedWindow,
                         mFocusedElement, mFirstBlurEvent, mFirstFocusEvent,
                         mWindowBeingLowered, mDelayedBlurFocusEvents,
                         mMouseButtonEventHandlingDocument)

nsFocusManager* nsFocusManager::sInstance = nullptr;
bool nsFocusManager::sMouseFocusesFormControl = false;
bool nsFocusManager::sTestMode = false;

static const char* kObservedPrefs[] = {
    "accessibility.browsewithcaret", "accessibility.tabfocus_applies_to_xul",
    "accessibility.mouse_focuses_formcontrol", "focusmanager.testmode",
    nullptr};

nsFocusManager::nsFocusManager() : mEventHandlingNeedsFlush(false) {}

nsFocusManager::~nsFocusManager() {
  Preferences::UnregisterCallbacks(
      PREF_CHANGE_METHOD(nsFocusManager::PrefChanged), kObservedPrefs, this);

  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
  if (obs) {
    obs->RemoveObserver(this, "xpcom-shutdown");
  }
}

// static
nsresult nsFocusManager::Init() {
  nsFocusManager* fm = new nsFocusManager();
  NS_ADDREF(fm);
  sInstance = fm;

  nsIContent::sTabFocusModelAppliesToXUL =
      Preferences::GetBool("accessibility.tabfocus_applies_to_xul",
                           nsIContent::sTabFocusModelAppliesToXUL);

  sMouseFocusesFormControl =
      Preferences::GetBool("accessibility.mouse_focuses_formcontrol", false);

  sTestMode = Preferences::GetBool("focusmanager.testmode", false);

  Preferences::RegisterCallbacks(
      PREF_CHANGE_METHOD(nsFocusManager::PrefChanged), kObservedPrefs, fm);

  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
  if (obs) {
    obs->AddObserver(fm, "xpcom-shutdown", true);
  }

  return NS_OK;
}

// static
void nsFocusManager::Shutdown() { NS_IF_RELEASE(sInstance); }

void nsFocusManager::PrefChanged(const char* aPref) {
  nsDependentCString pref(aPref);
  if (pref.EqualsLiteral("accessibility.browsewithcaret")) {
    UpdateCaretForCaretBrowsingMode();
  } else if (pref.EqualsLiteral("accessibility.tabfocus_applies_to_xul")) {
    nsIContent::sTabFocusModelAppliesToXUL =
        Preferences::GetBool("accessibility.tabfocus_applies_to_xul",
                             nsIContent::sTabFocusModelAppliesToXUL);
  } else if (pref.EqualsLiteral("accessibility.mouse_focuses_formcontrol")) {
    sMouseFocusesFormControl =
        Preferences::GetBool("accessibility.mouse_focuses_formcontrol", false);
  } else if (pref.EqualsLiteral("focusmanager.testmode")) {
    sTestMode = Preferences::GetBool("focusmanager.testmode", false);
  }
}

NS_IMETHODIMP
nsFocusManager::Observe(nsISupports* aSubject, const char* aTopic,
                        const char16_t* aData) {
  if (!nsCRT::strcmp(aTopic, "xpcom-shutdown")) {
    mActiveWindow = nullptr;
    mFocusedWindow = nullptr;
    mFocusedElement = nullptr;
    mFirstBlurEvent = nullptr;
    mFirstFocusEvent = nullptr;
    mWindowBeingLowered = nullptr;
    mDelayedBlurFocusEvents.Clear();
    mMouseButtonEventHandlingDocument = nullptr;
  }

  return NS_OK;
}

// given a frame content node, retrieve the nsIDOMWindow displayed in it
static nsPIDOMWindowOuter* GetContentWindow(nsIContent* aContent) {
  Document* doc = aContent->GetComposedDoc();
  if (doc) {
    Document* subdoc = doc->GetSubDocumentFor(aContent);
    if (subdoc) return subdoc->GetWindow();
  }

  return nullptr;
}

bool nsFocusManager::IsFocused(nsIContent* aContent) {
  if (!aContent || !mFocusedElement) {
    return false;
  }
  return aContent == mFocusedElement;
}

bool nsFocusManager::IsTestMode() { return sTestMode; }

// get the current window for the given content node
static nsPIDOMWindowOuter* GetCurrentWindow(nsIContent* aContent) {
  Document* doc = aContent->GetComposedDoc();
  return doc ? doc->GetWindow() : nullptr;
}

// static
Element* nsFocusManager::GetFocusedDescendant(
    nsPIDOMWindowOuter* aWindow, SearchRange aSearchRange,
    nsPIDOMWindowOuter** aFocusedWindow) {
  NS_ENSURE_TRUE(aWindow, nullptr);

  *aFocusedWindow = nullptr;

  Element* currentElement = nullptr;
  nsPIDOMWindowOuter* window = aWindow;
  for (;;) {
    *aFocusedWindow = window;
    currentElement = window->GetFocusedElement();
    if (!currentElement || aSearchRange == eOnlyCurrentWindow) {
      break;
    }

    window = GetContentWindow(currentElement);
    if (!window) {
      break;
    }

    if (aSearchRange == eIncludeAllDescendants) {
      continue;
    }

    MOZ_ASSERT(aSearchRange == eIncludeVisibleDescendants);

    // If the child window doesn't have PresShell, it means the window is
    // invisible.
    nsIDocShell* docShell = window->GetDocShell();
    if (!docShell) {
      break;
    }
    nsIPresShell* presShell = docShell->GetPresShell();
    if (!presShell) {
      break;
    }
  }

  NS_IF_ADDREF(*aFocusedWindow);

  return currentElement;
}

// static
Element* nsFocusManager::GetRedirectedFocus(nsIContent* aContent) {
  // For input number, redirect focus to our anonymous text control.
  if (aContent->IsHTMLElement(nsGkAtoms::input)) {
    bool typeIsNumber =
        static_cast<dom::HTMLInputElement*>(aContent)->ControlType() ==
        NS_FORM_INPUT_NUMBER;

    if (typeIsNumber) {
      nsNumberControlFrame* numberControlFrame =
          do_QueryFrame(aContent->GetPrimaryFrame());

      if (numberControlFrame) {
        HTMLInputElement* textControl =
            numberControlFrame->GetAnonTextControl();
        return textControl;
      }
    }
  }

#ifdef MOZ_XUL
  if (aContent->IsXULElement()) {
    if (aContent->IsXULElement(nsGkAtoms::textbox)) {
      return aContent->OwnerDoc()->GetAnonymousElementByAttribute(
          aContent, nsGkAtoms::anonid, NS_LITERAL_STRING("input"));
    } else {
      nsCOMPtr<nsIDOMXULMenuListElement> menulist =
          aContent->AsElement()->AsXULMenuList();
      if (menulist) {
        RefPtr<Element> inputField;
        menulist->GetInputField(getter_AddRefs(inputField));
        return inputField;
      }
    }
  }
#endif

  return nullptr;
}

// static
InputContextAction::Cause nsFocusManager::GetFocusMoveActionCause(
    uint32_t aFlags) {
  if (aFlags & nsIFocusManager::FLAG_BYTOUCH) {
    return InputContextAction::CAUSE_TOUCH;
  } else if (aFlags & nsIFocusManager::FLAG_BYMOUSE) {
    return InputContextAction::CAUSE_MOUSE;
  } else if (aFlags & nsIFocusManager::FLAG_BYKEY) {
    return InputContextAction::CAUSE_KEY;
  }
  return InputContextAction::CAUSE_UNKNOWN;
}

NS_IMETHODIMP
nsFocusManager::GetActiveWindow(mozIDOMWindowProxy** aWindow) {
  NS_IF_ADDREF(*aWindow = mActiveWindow);
  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::SetActiveWindow(mozIDOMWindowProxy* aWindow) {
  NS_ENSURE_STATE(aWindow);

  // only top-level windows can be made active
  nsCOMPtr<nsPIDOMWindowOuter> piWindow = nsPIDOMWindowOuter::From(aWindow);
  NS_ENSURE_TRUE(piWindow == piWindow->GetPrivateRoot(), NS_ERROR_INVALID_ARG);

  RaiseWindow(piWindow);
  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::GetFocusedWindow(mozIDOMWindowProxy** aFocusedWindow) {
  NS_IF_ADDREF(*aFocusedWindow = mFocusedWindow);
  return NS_OK;
}

NS_IMETHODIMP nsFocusManager::SetFocusedWindow(
    mozIDOMWindowProxy* aWindowToFocus) {
  LOGFOCUS(("<<SetFocusedWindow begin>>"));

  nsCOMPtr<nsPIDOMWindowOuter> windowToFocus =
      nsPIDOMWindowOuter::From(aWindowToFocus);
  NS_ENSURE_TRUE(windowToFocus, NS_ERROR_FAILURE);

  windowToFocus = windowToFocus->GetOuterWindow();

  nsCOMPtr<Element> frameElement = windowToFocus->GetFrameElementInternal();
  if (frameElement) {
    // pass false for aFocusChanged so that the caret does not get updated
    // and scrolling does not occur.
    SetFocusInner(frameElement, 0, false, true);
  } else {
    // this is a top-level window. If the window has a child frame focused,
    // clear the focus. Otherwise, focus should already be in this frame, or
    // already cleared. This ensures that focus will be in this frame and not
    // in a child.
    nsIContent* content = windowToFocus->GetFocusedElement();
    if (content) {
      if (nsCOMPtr<nsPIDOMWindowOuter> childWindow = GetContentWindow(content))
        ClearFocus(windowToFocus);
    }
  }

  nsCOMPtr<nsPIDOMWindowOuter> rootWindow = windowToFocus->GetPrivateRoot();
  if (rootWindow) RaiseWindow(rootWindow);

  LOGFOCUS(("<<SetFocusedWindow end>>"));

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::GetFocusedElement(Element** aFocusedElement) {
  RefPtr<Element> focusedElement = mFocusedElement;
  focusedElement.forget(aFocusedElement);
  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::GetLastFocusMethod(mozIDOMWindowProxy* aWindow,
                                   uint32_t* aLastFocusMethod) {
  // the focus method is stored on the inner window
  nsCOMPtr<nsPIDOMWindowOuter> window;
  if (aWindow) {
    window = nsPIDOMWindowOuter::From(aWindow);
  }
  if (!window) window = mFocusedWindow;

  *aLastFocusMethod = window ? window->GetFocusMethod() : 0;

  NS_ASSERTION((*aLastFocusMethod & FOCUSMETHOD_MASK) == *aLastFocusMethod,
               "invalid focus method");
  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::SetFocus(Element* aElement, uint32_t aFlags) {
  LOGFOCUS(("<<SetFocus begin>>"));

  NS_ENSURE_ARG(aElement);

  SetFocusInner(aElement, aFlags, true, true);

  LOGFOCUS(("<<SetFocus end>>"));

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::ElementIsFocusable(Element* aElement, uint32_t aFlags,
                                   bool* aIsFocusable) {
  NS_ENSURE_TRUE(aElement, NS_ERROR_INVALID_ARG);

  *aIsFocusable = CheckIfFocusable(aElement, aFlags) != nullptr;

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::MoveFocus(mozIDOMWindowProxy* aWindow, Element* aStartElement,
                          uint32_t aType, uint32_t aFlags, Element** aElement) {
  *aElement = nullptr;

  LOGFOCUS(("<<MoveFocus begin Type: %d Flags: %x>>", aType, aFlags));

  if (MOZ_LOG_TEST(gFocusLog, LogLevel::Debug) && mFocusedWindow) {
    Document* doc = mFocusedWindow->GetExtantDoc();
    if (doc && doc->GetDocumentURI()) {
      LOGFOCUS((" Focused Window: %p %s", mFocusedWindow.get(),
                doc->GetDocumentURI()->GetSpecOrDefault().get()));
    }
  }

  LOGCONTENT("  Current Focus: %s", mFocusedElement.get());

  // use FLAG_BYMOVEFOCUS when switching focus with MoveFocus unless one of
  // the other focus methods is already set, or we're just moving to the root
  // or caret position.
  if (aType != MOVEFOCUS_ROOT && aType != MOVEFOCUS_CARET &&
      (aFlags & FOCUSMETHOD_MASK) == 0) {
    aFlags |= FLAG_BYMOVEFOCUS;
  }

  nsCOMPtr<nsPIDOMWindowOuter> window;
  if (aStartElement) {
    window = GetCurrentWindow(aStartElement);
  } else {
    window = aWindow ? nsPIDOMWindowOuter::From(aWindow) : mFocusedWindow.get();
  }

  NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);

  bool noParentTraversal = aFlags & FLAG_NOPARENTFRAME;
  nsCOMPtr<nsIContent> newFocus;
  nsresult rv =
      DetermineElementToMoveFocus(window, aStartElement, aType,
                                  noParentTraversal, getter_AddRefs(newFocus));
  if (rv == NS_SUCCESS_DOM_NO_OPERATION) {
    return NS_OK;
  }

  NS_ENSURE_SUCCESS(rv, rv);

  LOGCONTENTNAVIGATION("Element to be focused: %s", newFocus.get());

  if (newFocus && newFocus->IsElement()) {
    // for caret movement, pass false for the aFocusChanged argument,
    // otherwise the caret will end up moving to the focus position. This
    // would be a problem because the caret would move to the beginning of the
    // focused link making it impossible to navigate the caret over a link.
    SetFocusInner(newFocus->AsElement(), aFlags, aType != MOVEFOCUS_CARET,
                  true);
    *aElement = do_AddRef(newFocus->AsElement()).take();
  } else if (aType == MOVEFOCUS_ROOT || aType == MOVEFOCUS_CARET) {
    // no content was found, so clear the focus for these two types.
    ClearFocus(window);
  }

  LOGFOCUS(("<<MoveFocus end>>"));

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::ClearFocus(mozIDOMWindowProxy* aWindow) {
  LOGFOCUS(("<<ClearFocus begin>>"));

  // if the window to clear is the focused window or an ancestor of the
  // focused window, then blur the existing focused content. Otherwise, the
  // focus is somewhere else so just update the current node.
  NS_ENSURE_TRUE(aWindow, NS_ERROR_INVALID_ARG);
  nsCOMPtr<nsPIDOMWindowOuter> window = nsPIDOMWindowOuter::From(aWindow);

  if (IsSameOrAncestor(window, mFocusedWindow)) {
    bool isAncestor = (window != mFocusedWindow);
    if (Blur(window, nullptr, isAncestor, true)) {
      // if we are clearing the focus on an ancestor of the focused window,
      // the ancestor will become the new focused window, so focus it
      if (isAncestor) Focus(window, nullptr, 0, true, false, false, true);
    }
  } else {
    window->SetFocusedElement(nullptr);
  }

  LOGFOCUS(("<<ClearFocus end>>"));

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::GetFocusedElementForWindow(mozIDOMWindowProxy* aWindow,
                                           bool aDeep,
                                           mozIDOMWindowProxy** aFocusedWindow,
                                           Element** aElement) {
  *aElement = nullptr;
  if (aFocusedWindow) *aFocusedWindow = nullptr;

  NS_ENSURE_TRUE(aWindow, NS_ERROR_INVALID_ARG);
  nsCOMPtr<nsPIDOMWindowOuter> window = nsPIDOMWindowOuter::From(aWindow);

  nsCOMPtr<nsPIDOMWindowOuter> focusedWindow;
  RefPtr<Element> focusedElement =
      GetFocusedDescendant(window,
                           aDeep ? nsFocusManager::eIncludeAllDescendants
                                 : nsFocusManager::eOnlyCurrentWindow,
                           getter_AddRefs(focusedWindow));

  focusedElement.forget(aElement);

  if (aFocusedWindow) NS_IF_ADDREF(*aFocusedWindow = focusedWindow);

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::MoveCaretToFocus(mozIDOMWindowProxy* aWindow) {
  nsCOMPtr<nsIWebNavigation> webnav = do_GetInterface(aWindow);
  nsCOMPtr<nsIDocShellTreeItem> dsti = do_QueryInterface(webnav);
  if (dsti) {
    if (dsti->ItemType() != nsIDocShellTreeItem::typeChrome) {
      nsCOMPtr<nsIDocShell> docShell = do_QueryInterface(dsti);
      NS_ENSURE_TRUE(docShell, NS_ERROR_FAILURE);

      // don't move the caret for editable documents
      bool isEditable;
      docShell->GetEditable(&isEditable);
      if (isEditable) return NS_OK;

      nsCOMPtr<nsIPresShell> presShell = docShell->GetPresShell();
      NS_ENSURE_TRUE(presShell, NS_ERROR_FAILURE);

      nsCOMPtr<nsPIDOMWindowOuter> window = nsPIDOMWindowOuter::From(aWindow);
      nsCOMPtr<nsIContent> content = window->GetFocusedElement();
      if (content) MoveCaretToFocus(presShell, content);
    }
  }

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::WindowRaised(mozIDOMWindowProxy* aWindow) {
  NS_ENSURE_TRUE(aWindow, NS_ERROR_INVALID_ARG);
  nsCOMPtr<nsPIDOMWindowOuter> window = nsPIDOMWindowOuter::From(aWindow);

  if (MOZ_LOG_TEST(gFocusLog, LogLevel::Debug)) {
    LOGFOCUS(("Window %p Raised [Currently: %p %p]", aWindow,
              mActiveWindow.get(), mFocusedWindow.get()));
    Document* doc = window->GetExtantDoc();
    if (doc && doc->GetDocumentURI()) {
      LOGFOCUS(("  Raised Window: %p %s", aWindow,
                doc->GetDocumentURI()->GetSpecOrDefault().get()));
    }
    if (mActiveWindow) {
      doc = mActiveWindow->GetExtantDoc();
      if (doc && doc->GetDocumentURI()) {
        LOGFOCUS(("  Active Window: %p %s", mActiveWindow.get(),
                  doc->GetDocumentURI()->GetSpecOrDefault().get()));
      }
    }
  }

  if (mActiveWindow == window) {
    // The window is already active, so there is no need to focus anything,
    // but make sure that the right widget is focused. This is a special case
    // for Windows because when restoring a minimized window, a second
    // activation will occur and the top-level widget could be focused instead
    // of the child we want. We solve this by calling SetFocus to ensure that
    // what the focus manager thinks should be the current widget is actually
    // focused.
    EnsureCurrentWidgetFocused();
    return NS_OK;
  }

  // lower the existing window, if any. This shouldn't happen usually.
  if (mActiveWindow) WindowLowered(mActiveWindow);

  nsCOMPtr<nsIDocShellTreeItem> docShellAsItem = window->GetDocShell();
  // If there's no docShellAsItem, this window must have been closed,
  // in that case there is no tree owner.
  NS_ENSURE_TRUE(docShellAsItem, NS_OK);

  // set this as the active window
  mActiveWindow = window;

  // ensure that the window is enabled and visible
  nsCOMPtr<nsIDocShellTreeOwner> treeOwner;
  docShellAsItem->GetTreeOwner(getter_AddRefs(treeOwner));
  nsCOMPtr<nsIBaseWindow> baseWindow = do_QueryInterface(treeOwner);
  if (baseWindow) {
    bool isEnabled = true;
    if (NS_SUCCEEDED(baseWindow->GetEnabled(&isEnabled)) && !isEnabled) {
      return NS_ERROR_FAILURE;
    }

    baseWindow->SetVisibility(true);
  }

  // If this is a parent or single process window, send the activate event.
  // Events for child process windows will be sent when ParentActivated
  // is called.
  if (XRE_IsParentProcess()) {
    ActivateOrDeactivate(window, true);
  }

  // retrieve the last focused element within the window that was raised
  nsCOMPtr<nsPIDOMWindowOuter> currentWindow;
  RefPtr<Element> currentFocus = GetFocusedDescendant(
      window, eIncludeAllDescendants, getter_AddRefs(currentWindow));

  NS_ASSERTION(currentWindow, "window raised with no window current");
  if (!currentWindow) return NS_OK;

  // If there is no nsIXULWindow, then this is an embedded or child process
  // window. Pass false for aWindowRaised so that commands get updated.
  nsCOMPtr<nsIXULWindow> xulWin(do_GetInterface(baseWindow));
  Focus(currentWindow, currentFocus, 0, true, false, xulWin != nullptr, true);

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::WindowLowered(mozIDOMWindowProxy* aWindow) {
  NS_ENSURE_TRUE(aWindow, NS_ERROR_INVALID_ARG);
  nsCOMPtr<nsPIDOMWindowOuter> window = nsPIDOMWindowOuter::From(aWindow);

  if (MOZ_LOG_TEST(gFocusLog, LogLevel::Debug)) {
    LOGFOCUS(("Window %p Lowered [Currently: %p %p]", aWindow,
              mActiveWindow.get(), mFocusedWindow.get()));
    Document* doc = window->GetExtantDoc();
    if (doc && doc->GetDocumentURI()) {
      LOGFOCUS(("  Lowered Window: %s",
                doc->GetDocumentURI()->GetSpecOrDefault().get()));
    }
    if (mActiveWindow) {
      doc = mActiveWindow->GetExtantDoc();
      if (doc && doc->GetDocumentURI()) {
        LOGFOCUS(("  Active Window: %s",
                  doc->GetDocumentURI()->GetSpecOrDefault().get()));
      }
    }
  }

  if (mActiveWindow != window) return NS_OK;

  // clear the mouse capture as the active window has changed
  nsIPresShell::SetCapturingContent(nullptr, 0);

  // In addition, reset the drag state to ensure that we are no longer in
  // drag-select mode.
  if (mFocusedWindow) {
    nsCOMPtr<nsIDocShell> docShell = mFocusedWindow->GetDocShell();
    if (docShell) {
      nsCOMPtr<nsIPresShell> presShell = docShell->GetPresShell();
      if (presShell) {
        RefPtr<nsFrameSelection> frameSelection = presShell->FrameSelection();
        frameSelection->SetDragState(false);
      }
    }
  }

  // If this is a parent or single process window, send the deactivate event.
  // Events for child process windows will be sent when ParentActivated
  // is called.
  if (XRE_IsParentProcess()) {
    ActivateOrDeactivate(window, false);
  }

  // keep track of the window being lowered, so that attempts to raise the
  // window can be prevented until we return. Otherwise, focus can get into
  // an unusual state.
  mWindowBeingLowered = mActiveWindow;
  mActiveWindow = nullptr;

  if (mFocusedWindow) Blur(nullptr, nullptr, true, true);

  mWindowBeingLowered = nullptr;

  return NS_OK;
}

nsresult nsFocusManager::ContentRemoved(Document* aDocument,
                                        nsIContent* aContent) {
  NS_ENSURE_ARG(aDocument);
  NS_ENSURE_ARG(aContent);

  nsPIDOMWindowOuter* window = aDocument->GetWindow();
  if (!window) return NS_OK;

  // if the content is currently focused in the window, or is an
  // shadow-including inclusive ancestor of the currently focused element,
  // reset the focus within that window.
  nsIContent* content = window->GetFocusedElement();
  if (content &&
      nsContentUtils::ContentIsHostIncludingDescendantOf(content, aContent)) {
    bool shouldShowFocusRing = window->ShouldShowFocusRing();
    window->SetFocusedElement(nullptr);

    // if this window is currently focused, clear the global focused
    // element as well, but don't fire any events.
    if (window == mFocusedWindow) {
      mFocusedElement = nullptr;
    } else {
      // Check if the node that was focused is an iframe or similar by looking
      // if it has a subdocument. This would indicate that this focused iframe
      // and its descendants will be going away. We will need to move the
      // focus somewhere else, so just clear the focus in the toplevel window
      // so that no element is focused.
      Document* subdoc = aDocument->GetSubDocumentFor(content);
      if (subdoc) {
        nsCOMPtr<nsIDocShell> docShell = subdoc->GetDocShell();
        if (docShell) {
          nsCOMPtr<nsPIDOMWindowOuter> childWindow = docShell->GetWindow();
          if (childWindow && IsSameOrAncestor(childWindow, mFocusedWindow)) {
            ClearFocus(mActiveWindow);
          }
        }
      }
    }

    // Notify the editor in case we removed its ancestor limiter.
    if (content->IsEditable()) {
      nsCOMPtr<nsIDocShell> docShell = aDocument->GetDocShell();
      if (docShell) {
        RefPtr<HTMLEditor> htmlEditor = docShell->GetHTMLEditor();
        if (htmlEditor) {
          RefPtr<Selection> selection = htmlEditor->GetSelection();
          if (selection && selection->GetFrameSelection() &&
              content == selection->GetFrameSelection()->GetAncestorLimiter()) {
            htmlEditor->FinalizeSelection();
          }
        }
      }
    }

    NotifyFocusStateChange(content, nullptr, shouldShowFocusRing, false);
  }

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::WindowShown(mozIDOMWindowProxy* aWindow, bool aNeedsFocus) {
  NS_ENSURE_TRUE(aWindow, NS_ERROR_INVALID_ARG);
  nsCOMPtr<nsPIDOMWindowOuter> window = nsPIDOMWindowOuter::From(aWindow);

  if (MOZ_LOG_TEST(gFocusLog, LogLevel::Debug)) {
    LOGFOCUS(("Window %p Shown [Currently: %p %p]", window.get(),
              mActiveWindow.get(), mFocusedWindow.get()));
    Document* doc = window->GetExtantDoc();
    if (doc && doc->GetDocumentURI()) {
      LOGFOCUS(("Shown Window: %s",
                doc->GetDocumentURI()->GetSpecOrDefault().get()));
    }

    if (mFocusedWindow) {
      doc = mFocusedWindow->GetExtantDoc();
      if (doc && doc->GetDocumentURI()) {
        LOGFOCUS((" Focused Window: %s",
                  doc->GetDocumentURI()->GetSpecOrDefault().get()));
      }
    }
  }

  if (nsIDocShell* docShell = window->GetDocShell()) {
    if (nsCOMPtr<nsITabChild> child = docShell->GetTabChild()) {
      bool active = static_cast<TabChild*>(child.get())->ParentIsActive();
      ActivateOrDeactivate(window, active);
    }
  }

  if (mFocusedWindow != window) return NS_OK;

  if (aNeedsFocus) {
    nsCOMPtr<nsPIDOMWindowOuter> currentWindow;
    RefPtr<Element> currentFocus = GetFocusedDescendant(
        window, eIncludeAllDescendants, getter_AddRefs(currentWindow));
    if (currentWindow)
      Focus(currentWindow, currentFocus, 0, true, false, false, true);
  } else {
    // Sometimes, an element in a window can be focused before the window is
    // visible, which would mean that the widget may not be properly focused.
    // When the window becomes visible, make sure the right widget is focused.
    EnsureCurrentWidgetFocused();
  }

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::WindowHidden(mozIDOMWindowProxy* aWindow) {
  // if there is no window or it is not the same or an ancestor of the
  // currently focused window, just return, as the current focus will not
  // be affected.

  NS_ENSURE_TRUE(aWindow, NS_ERROR_INVALID_ARG);
  nsCOMPtr<nsPIDOMWindowOuter> window = nsPIDOMWindowOuter::From(aWindow);

  if (MOZ_LOG_TEST(gFocusLog, LogLevel::Debug)) {
    LOGFOCUS(("Window %p Hidden [Currently: %p %p]", window.get(),
              mActiveWindow.get(), mFocusedWindow.get()));
    nsAutoCString spec;
    Document* doc = window->GetExtantDoc();
    if (doc && doc->GetDocumentURI()) {
      LOGFOCUS(("  Hide Window: %s",
                doc->GetDocumentURI()->GetSpecOrDefault().get()));
    }

    if (mFocusedWindow) {
      doc = mFocusedWindow->GetExtantDoc();
      if (doc && doc->GetDocumentURI()) {
        LOGFOCUS(("  Focused Window: %s",
                  doc->GetDocumentURI()->GetSpecOrDefault().get()));
      }
    }

    if (mActiveWindow) {
      doc = mActiveWindow->GetExtantDoc();
      if (doc && doc->GetDocumentURI()) {
        LOGFOCUS(("  Active Window: %s",
                  doc->GetDocumentURI()->GetSpecOrDefault().get()));
      }
    }
  }

  if (!IsSameOrAncestor(window, mFocusedWindow)) return NS_OK;

  // at this point, we know that the window being hidden is either the focused
  // window, or an ancestor of the focused window. Either way, the focus is no
  // longer valid, so it needs to be updated.

  RefPtr<Element> oldFocusedElement = mFocusedElement.forget();

  nsCOMPtr<nsIDocShell> focusedDocShell = mFocusedWindow->GetDocShell();
  nsCOMPtr<nsIPresShell> presShell = focusedDocShell->GetPresShell();

  if (oldFocusedElement && oldFocusedElement->IsInComposedDoc()) {
    NotifyFocusStateChange(oldFocusedElement, nullptr,
                           mFocusedWindow->ShouldShowFocusRing(), false);
    window->UpdateCommands(NS_LITERAL_STRING("focus"), nullptr, 0);

    if (presShell) {
      SendFocusOrBlurEvent(eBlur, presShell,
                           oldFocusedElement->GetComposedDoc(),
                           oldFocusedElement, 1, false);
    }
  }

  nsPresContext* focusedPresContext =
      presShell ? presShell->GetPresContext() : nullptr;
  IMEStateManager::OnChangeFocus(focusedPresContext, nullptr,
                                 GetFocusMoveActionCause(0));
  if (presShell) {
    SetCaretVisible(presShell, false, nullptr);
  }

  // if the docshell being hidden is being destroyed, then we want to move
  // focus somewhere else. Call ClearFocus on the toplevel window, which
  // will have the effect of clearing the focus and moving the focused window
  // to the toplevel window. But if the window isn't being destroyed, we are
  // likely just loading a new document in it, so we want to maintain the
  // focused window so that the new document gets properly focused.
  nsCOMPtr<nsIDocShell> docShellBeingHidden = window->GetDocShell();
  bool beingDestroyed = !docShellBeingHidden;
  if (docShellBeingHidden) {
    docShellBeingHidden->IsBeingDestroyed(&beingDestroyed);
  }
  if (beingDestroyed) {
    // There is usually no need to do anything if a toplevel window is going
    // away, as we assume that WindowLowered will be called. However, this may
    // not happen if nsIAppStartup::eForceQuit is used to quit, and can cause
    // a leak. So if the active window is being destroyed, call WindowLowered
    // directly.
    if (mActiveWindow == mFocusedWindow || mActiveWindow == window)
      WindowLowered(mActiveWindow);
    else
      ClearFocus(mActiveWindow);
    return NS_OK;
  }

  // if the window being hidden is an ancestor of the focused window, adjust
  // the focused window so that it points to the one being hidden. This
  // ensures that the focused window isn't in a chain of frames that doesn't
  // exist any more.
  if (window != mFocusedWindow) {
    nsCOMPtr<nsIDocShellTreeItem> dsti =
        mFocusedWindow ? mFocusedWindow->GetDocShell() : nullptr;
    if (dsti) {
      nsCOMPtr<nsIDocShellTreeItem> parentDsti;
      dsti->GetParent(getter_AddRefs(parentDsti));
      if (parentDsti) {
        if (nsCOMPtr<nsPIDOMWindowOuter> parentWindow = parentDsti->GetWindow())
          parentWindow->SetFocusedElement(nullptr);
      }
    }

    SetFocusedWindowInternal(window);
  }

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::FireDelayedEvents(Document* aDocument) {
  NS_ENSURE_ARG(aDocument);

  // fire any delayed focus and blur events in the same order that they were
  // added
  for (uint32_t i = 0; i < mDelayedBlurFocusEvents.Length(); i++) {
    if (mDelayedBlurFocusEvents[i].mDocument == aDocument) {
      if (!aDocument->GetInnerWindow() ||
          !aDocument->GetInnerWindow()->IsCurrentInnerWindow()) {
        // If the document was navigated away from or is defunct, don't bother
        // firing events on it. Note the symmetry between this condition and
        // the similar one in Document.cpp:FireOrClearDelayedEvents.
        mDelayedBlurFocusEvents.RemoveElementAt(i);
        --i;
      } else if (!aDocument->EventHandlingSuppressed()) {
        EventMessage message = mDelayedBlurFocusEvents[i].mEventMessage;
        nsCOMPtr<EventTarget> target = mDelayedBlurFocusEvents[i].mTarget;
        nsCOMPtr<nsIPresShell> presShell =
            mDelayedBlurFocusEvents[i].mPresShell;
        nsCOMPtr<EventTarget> relatedTarget =
            mDelayedBlurFocusEvents[i].mRelatedTarget;
        mDelayedBlurFocusEvents.RemoveElementAt(i);

        FireFocusOrBlurEvent(message, presShell, target, false, false,
                             relatedTarget);
        --i;
      }
    }
  }

  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::FocusPlugin(Element* aPlugin) {
  NS_ENSURE_ARG(aPlugin);
  SetFocusInner(aPlugin, 0, true, false);
  return NS_OK;
}

NS_IMETHODIMP
nsFocusManager::ParentActivated(mozIDOMWindowProxy* aWindow, bool aActive) {
  nsCOMPtr<nsPIDOMWindowOuter> window = nsPIDOMWindowOuter::From(aWindow);
  NS_ENSURE_TRUE(window, NS_ERROR_INVALID_ARG);

  ActivateOrDeactivate(window, aActive);
  return NS_OK;
}

/* static */
void nsFocusManager::NotifyFocusStateChange(nsIContent* aContent,
                                            nsIContent* aContentToFocus,
                                            bool aWindowShouldShowFocusRing,
                                            bool aGettingFocus) {
  MOZ_ASSERT_IF(aContentToFocus, !aGettingFocus);
  if (!aContent->IsElement()) {
    return;
  }

  nsIContent* commonAncestor = nullptr;
  if (aContentToFocus && aContentToFocus->IsElement()) {
    commonAncestor = nsContentUtils::GetCommonFlattenedTreeAncestor(
        aContent, aContentToFocus);
  }

  EventStates eventState = NS_EVENT_STATE_FOCUS;
  if (aWindowShouldShowFocusRing) {
    eventState |= NS_EVENT_STATE_FOCUSRING;
  }

  if (aGettingFocus) {
    aContent->AsElement()->AddStates(eventState);
  } else {
    aContent->AsElement()->RemoveStates(eventState);
  }

  for (nsIContent* content = aContent; content && content != commonAncestor;
       content = content->GetFlattenedTreeParent()) {
    if (!content->IsElement()) {
      continue;
    }

    Element* element = content->AsElement();
    if (aGettingFocus) {
      if (element->State().HasState(NS_EVENT_STATE_FOCUS_WITHIN)) {
        break;
      }
      element->AddStates(NS_EVENT_STATE_FOCUS_WITHIN);
    } else {
      element->RemoveStates(NS_EVENT_STATE_FOCUS_WITHIN);
    }
  }
}

// static
void nsFocusManager::EnsureCurrentWidgetFocused() {
  if (!mFocusedWindow || sTestMode) return;

  // get the main child widget for the focused window and ensure that the
  // platform knows that this widget is focused.
  nsCOMPtr<nsIDocShell> docShell = mFocusedWindow->GetDocShell();
  if (docShell) {
    nsCOMPtr<nsIPresShell> presShell = docShell->GetPresShell();
    if (presShell) {
      nsViewManager* vm = presShell->GetViewManager();
      if (vm) {
        nsCOMPtr<nsIWidget> widget;
        vm->GetRootWidget(getter_AddRefs(widget));
        if (widget) widget->SetFocus(false);
      }
    }
  }
}

bool ActivateOrDeactivateChild(TabParent* aParent, void* aArg) {
  bool active = static_cast<bool>(aArg);
  Unused << aParent->SendParentActivated(active);
  return false;
}

void nsFocusManager::ActivateOrDeactivate(nsPIDOMWindowOuter* aWindow,
                                          bool aActive) {
  if (!aWindow) {
    return;
  }

  // Inform the DOM window that it has activated or deactivated, so that
  // the active attribute is updated on the window.
  aWindow->ActivateOrDeactivate(aActive);

  // Send the activate event.
  if (aWindow->GetExtantDoc()) {
    nsContentUtils::DispatchEventOnlyToChrome(
        aWindow->GetExtantDoc(), aWindow->GetCurrentInnerWindow(),
        aActive ? NS_LITERAL_STRING("activate")
                : NS_LITERAL_STRING("deactivate"),
        CanBubble::eYes, Cancelable::eYes, nullptr);
  }

  // Look for any remote child frames, iterate over them and send the activation
  // notification.
  nsContentUtils::CallOnAllRemoteChildren(aWindow, ActivateOrDeactivateChild,
                                          (void*)aActive);
}

void nsFocusManager::SetFocusInner(Element* aNewContent, int32_t aFlags,
                                   bool aFocusChanged, bool aAdjustWidget) {
  // if the element is not focusable, just return and leave the focus as is
  RefPtr<Element> elementToFocus = CheckIfFocusable(aNewContent, aFlags);
  if (!elementToFocus) {
    return;
  }

  // check if the element to focus is a frame (iframe) containing a child
  // document. Frames are never directly focused; instead focusing a frame
  // means focus what is inside the frame. To do this, the descendant content
  // within the frame is retrieved and that will be focused instead.
  nsCOMPtr<nsPIDOMWindowOuter> newWindow;
  nsCOMPtr<nsPIDOMWindowOuter> subWindow = GetContentWindow(elementToFocus);
  if (subWindow) {
    elementToFocus = GetFocusedDescendant(subWindow, eIncludeAllDescendants,
                                          getter_AddRefs(newWindow));
    // since a window is being refocused, clear aFocusChanged so that the
    // caret position isn't updated.
    aFocusChanged = false;
  }

  // unless it was set above, retrieve the window for the element to focus
  if (!newWindow) {
    newWindow = GetCurrentWindow(elementToFocus);
  }

  // if the element is already focused, just return. Note that this happens
  // after the frame check above so that we compare the element that will be
  // focused rather than the frame it is in.
  if (!newWindow ||
      (newWindow == mFocusedWindow && elementToFocus == mFocusedElement)) {
    return;
  }

  // don't allow focus to be placed in docshells or descendants of docshells
  // that are being destroyed. Also, ensure that the page hasn't been
  // unloaded. The prevents content from being refocused during an unload event.
  nsCOMPtr<nsIDocShell> newDocShell = newWindow->GetDocShell();
  nsCOMPtr<nsIDocShell> docShell = newDocShell;
  while (docShell) {
    bool inUnload;
    docShell->GetIsInUnload(&inUnload);
    if (inUnload) return;

    bool beingDestroyed;
    docShell->IsBeingDestroyed(&beingDestroyed);
    if (beingDestroyed) return;

    nsCOMPtr<nsIDocShellTreeItem> parentDsti;
    docShell->GetParent(getter_AddRefs(parentDsti));
    docShell = do_QueryInterface(parentDsti);
  }

  // if the new element is in the same window as the currently focused element
  bool isElementInFocusedWindow = (mFocusedWindow == newWindow);

  if (!isElementInFocusedWindow && mFocusedWindow && newWindow &&
      nsContentUtils::IsHandlingKeyBoardEvent()) {
    nsCOMPtr<nsIScriptObjectPrincipal> focused =
        do_QueryInterface(mFocusedWindow);
    nsCOMPtr<nsIScriptObjectPrincipal> newFocus = do_QueryInterface(newWindow);
    nsIPrincipal* focusedPrincipal = focused->GetPrincipal();
    nsIPrincipal* newPrincipal = newFocus->GetPrincipal();
    if (!focusedPrincipal || !newPrincipal) {
      return;
    }
    bool subsumes = false;
    focusedPrincipal->Subsumes(newPrincipal, &subsumes);
    if (!subsumes && !nsContentUtils::LegacyIsCallerChromeOrNativeCode()) {
      NS_WARNING("Not allowed to focus the new window!");
      return;
    }
  }

  // to check if the new element is in the active window, compare the
  // new root docshell for the new element with the active window's docshell.
  bool isElementInActiveWindow = false;

  nsCOMPtr<nsIDocShellTreeItem> dsti = newWindow->GetDocShell();
  nsCOMPtr<nsPIDOMWindowOuter> newRootWindow;
  if (dsti) {
    nsCOMPtr<nsIDocShellTreeItem> root;
    dsti->GetRootTreeItem(getter_AddRefs(root));
    newRootWindow = root ? root->GetWindow() : nullptr;

    isElementInActiveWindow = (mActiveWindow && newRootWindow == mActiveWindow);
  }

  // Exit fullscreen if we're focusing a windowed plugin on a non-MacOSX
  // system. We don't control event dispatch to windowed plugins on non-MacOSX,
  // so we can't display the "Press ESC to leave fullscreen mode" warning on
  // key input if a windowed plugin is focused, so just exit fullscreen
  // to guard against phishing.
#ifndef XP_MACOSX
  if (elementToFocus &&
      nsContentUtils::GetRootDocument(elementToFocus->OwnerDoc())
          ->GetFullscreenElement() &&
      nsContentUtils::HasPluginWithUncontrolledEventDispatch(elementToFocus)) {
    nsContentUtils::ReportToConsole(
        nsIScriptError::warningFlag, NS_LITERAL_CSTRING("DOM"),
        elementToFocus->OwnerDoc(), nsContentUtils::eDOM_PROPERTIES,
        "FocusedWindowedPluginWhileFullscreen");
    Document::AsyncExitFullscreen(elementToFocus->OwnerDoc());
  }
#endif

  // if the FLAG_NOSWITCHFRAME flag is used, only allow the focus to be
  // shifted away from the current element if the new shell to focus is
  // the same or an ancestor shell of the currently focused shell.
  bool allowFrameSwitch = !(aFlags & FLAG_NOSWITCHFRAME) ||
                          IsSameOrAncestor(newWindow, mFocusedWindow);

  // if the element is in the active window, frame switching is allowed and
  // the content is in a visible window, fire blur and focus events.
  bool sendFocusEvent =
      isElementInActiveWindow && allowFrameSwitch && IsWindowVisible(newWindow);

  // When the following conditions are true:
  //  * an element has focus
  //  * isn't called by trusted event (i.e., called by untrusted event or by js)
  //  * the focus is moved to another document's element
  // we need to check the permission.
  if (sendFocusEvent && mFocusedElement &&
      !nsContentUtils::LegacyIsCallerNativeCode() &&
      mFocusedElement->OwnerDoc() != aNewContent->OwnerDoc()) {
    // If the caller cannot access the current focused node, the caller should
    // not be able to steal focus from it. E.g., When the current focused node
    // is in chrome, any web contents should not be able to steal the focus.
    sendFocusEvent = nsContentUtils::CanCallerAccess(mFocusedElement);
    if (!sendFocusEvent && mMouseButtonEventHandlingDocument) {
      // However, while mouse button event is handling, the handling document's
      // script should be able to steal focus.
      sendFocusEvent =
          nsContentUtils::CanCallerAccess(mMouseButtonEventHandlingDocument);
    }
  }

  LOGCONTENT("Shift Focus: %s", elementToFocus.get());
  LOGFOCUS((" Flags: %x Current Window: %p New Window: %p Current Element: %p",
            aFlags, mFocusedWindow.get(), newWindow.get(),
            mFocusedElement.get()));
  LOGFOCUS((" In Active Window: %d In Focused Window: %d SendFocus: %d",
            isElementInActiveWindow, isElementInFocusedWindow, sendFocusEvent));

  if (sendFocusEvent) {
    RefPtr<Element> oldFocusedElement = mFocusedElement;
    // return if blurring fails or the focus changes during the blur
    if (mFocusedWindow) {
      // if the focus is being moved to another element in the same document,
      // or to a descendant, pass the existing window to Blur so that the
      // current node in the existing window is cleared. If moving to a
      // window elsewhere, we want to maintain the current node in the
      // window but still blur it.
      bool currentIsSameOrAncestor =
          IsSameOrAncestor(mFocusedWindow, newWindow);
      // find the common ancestor of the currently focused window and the new
      // window. The ancestor will need to have its currently focused node
      // cleared once the document has been blurred. Otherwise, we'll be in a
      // state where a document is blurred yet the chain of windows above it
      // still points to that document.
      // For instance, in the following frame tree:
      //   A
      //  B C
      //  D
      // D is focused and we want to focus C. Once D has been blurred, we need
      // to clear out the focus in A, otherwise A would still maintain that B
      // was focused, and B that D was focused.
      nsCOMPtr<nsPIDOMWindowOuter> commonAncestor;
      if (!isElementInFocusedWindow)
        commonAncestor = GetCommonAncestor(newWindow, mFocusedWindow);

      if (!Blur(currentIsSameOrAncestor ? mFocusedWindow.get() : nullptr,
                commonAncestor, !isElementInFocusedWindow, aAdjustWidget,
                elementToFocus)) {
        return;
      }
    }

    Focus(newWindow, elementToFocus, aFlags, !isElementInFocusedWindow,
          aFocusChanged, false, aAdjustWidget, oldFocusedElement);
  } else {
    // otherwise, for inactive windows and when the caller cannot steal the
    // focus, update the node in the window, and  raise the window if desired.
    if (allowFrameSwitch) AdjustWindowFocus(newWindow, true);

    // set the focus node and method as needed
    uint32_t focusMethod =
        aFocusChanged ? aFlags & FOCUSMETHODANDRING_MASK
                      : newWindow->GetFocusMethod() | (aFlags & FLAG_SHOWRING);
    newWindow->SetFocusedElement(elementToFocus, focusMethod);
    if (aFocusChanged) {
      nsCOMPtr<nsIDocShell> docShell = newWindow->GetDocShell();

      nsCOMPtr<nsIPresShell> presShell = docShell->GetPresShell();
      if (presShell && presShell->DidInitialize())
        ScrollIntoView(presShell, elementToFocus, aFlags);
    }

    // update the commands even when inactive so that the attributes for that
    // window are up to date.
    if (allowFrameSwitch)
      newWindow->UpdateCommands(NS_LITERAL_STRING("focus"), nullptr, 0);

    if (aFlags & FLAG_RAISE) RaiseWindow(newRootWindow);
  }
}

bool nsFocusManager::IsSameOrAncestor(nsPIDOMWindowOuter* aPossibleAncestor,
                                      nsPIDOMWindowOuter* aWindow) {
  if (!aWindow || !aPossibleAncestor) {
    return false;
  }

  nsCOMPtr<nsIDocShellTreeItem> ancestordsti = aPossibleAncestor->GetDocShell();
  nsCOMPtr<nsIDocShellTreeItem> dsti = aWindow->GetDocShell();
  while (dsti) {
    if (dsti == ancestordsti) return true;
    nsCOMPtr<nsIDocShellTreeItem> parentDsti;
    dsti->GetParent(getter_AddRefs(parentDsti));
    dsti.swap(parentDsti);
  }

  return false;
}

already_AddRefed<nsPIDOMWindowOuter> nsFocusManager::GetCommonAncestor(
    nsPIDOMWindowOuter* aWindow1, nsPIDOMWindowOuter* aWindow2) {
  NS_ENSURE_TRUE(aWindow1 && aWindow2, nullptr);

  nsCOMPtr<nsIDocShellTreeItem> dsti1 = aWindow1->GetDocShell();
  NS_ENSURE_TRUE(dsti1, nullptr);

  nsCOMPtr<nsIDocShellTreeItem> dsti2 = aWindow2->GetDocShell();
  NS_ENSURE_TRUE(dsti2, nullptr);

  AutoTArray<nsIDocShellTreeItem*, 30> parents1, parents2;
  do {
    parents1.AppendElement(dsti1);
    nsCOMPtr<nsIDocShellTreeItem> parentDsti1;
    dsti1->GetParent(getter_AddRefs(parentDsti1));
    dsti1.swap(parentDsti1);
  } while (dsti1);
  do {
    parents2.AppendElement(dsti2);
    nsCOMPtr<nsIDocShellTreeItem> parentDsti2;
    dsti2->GetParent(getter_AddRefs(parentDsti2));
    dsti2.swap(parentDsti2);
  } while (dsti2);

  uint32_t pos1 = parents1.Length();
  uint32_t pos2 = parents2.Length();
  nsIDocShellTreeItem* parent = nullptr;
  uint32_t len;
  for (len = std::min(pos1, pos2); len > 0; --len) {
    nsIDocShellTreeItem* child1 = parents1.ElementAt(--pos1);
    nsIDocShellTreeItem* child2 = parents2.ElementAt(--pos2);
    if (child1 != child2) {
      break;
    }
    parent = child1;
  }

  nsCOMPtr<nsPIDOMWindowOuter> window = parent ? parent->GetWindow() : nullptr;
  return window.forget();
}

void nsFocusManager::AdjustWindowFocus(nsPIDOMWindowOuter* aWindow,
                                       bool aCheckPermission) {
  bool isVisible = IsWindowVisible(aWindow);

  nsCOMPtr<nsPIDOMWindowOuter> window(aWindow);
  while (window) {
    // get the containing <iframe> or equivalent element so that it can be
    // focused below.
    nsCOMPtr<Element> frameElement = window->GetFrameElementInternal();

    nsCOMPtr<nsIDocShellTreeItem> dsti = window->GetDocShell();
    if (!dsti) return;
    nsCOMPtr<nsIDocShellTreeItem> parentDsti;
    dsti->GetParent(getter_AddRefs(parentDsti));
    if (!parentDsti) {
      return;
    }

    window = parentDsti->GetWindow();
    if (window) {
      // if the parent window is visible but aWindow was not, then we have
      // likely moved up and out from a hidden tab to the browser window, or a
      // similar such arrangement. Stop adjusting the current nodes.
      if (IsWindowVisible(window) != isVisible) break;

      // When aCheckPermission is true, we should check whether the caller can
      // access the window or not.  If it cannot access, we should stop the
      // adjusting.
      if (aCheckPermission && !nsContentUtils::LegacyIsCallerNativeCode() &&
          !nsContentUtils::CanCallerAccess(window->GetCurrentInnerWindow())) {
        break;
      }

      window->SetFocusedElement(frameElement);
    }
  }
}

bool nsFocusManager::IsWindowVisible(nsPIDOMWindowOuter* aWindow) {
  if (!aWindow || aWindow->IsFrozen()) return false;

  // Check if the inner window is frozen as well. This can happen when a focus
  // change occurs while restoring a previous page.
  nsPIDOMWindowInner* innerWindow = aWindow->GetCurrentInnerWindow();
  if (!innerWindow || innerWindow->IsFrozen()) return false;

  nsCOMPtr<nsIDocShell> docShell = aWindow->GetDocShell();
  nsCOMPtr<nsIBaseWindow> baseWin(do_QueryInterface(docShell));
  if (!baseWin) return false;

  bool visible = false;
  baseWin->GetVisibility(&visible);
  return visible;
}

bool nsFocusManager::IsNonFocusableRoot(nsIContent* aContent) {
  MOZ_ASSERT(aContent, "aContent must not be NULL");
  MOZ_ASSERT(aContent->IsInComposedDoc(), "aContent must be in a document");

  // If aContent is in designMode, the root element is not focusable.
  // NOTE: in designMode, most elements are not focusable, just the document is
  //       focusable.
  // Also, if aContent is not editable but it isn't in designMode, it's not
  // focusable.
  // And in userfocusignored context nothing is focusable.
  Document* doc = aContent->GetComposedDoc();
  NS_ASSERTION(doc, "aContent must have current document");
  return aContent == doc->GetRootElement() &&
         (doc->HasFlag(NODE_IS_EDITABLE) || !aContent->IsEditable() ||
          nsContentUtils::IsUserFocusIgnored(aContent));
}

Element* nsFocusManager::CheckIfFocusable(Element* aElement, uint32_t aFlags) {
  if (!aElement) return nullptr;

  // this is a special case for some XUL elements or input number, where an
  // anonymous child is actually focusable and not the element itself.
  RefPtr<Element> redirectedFocus = GetRedirectedFocus(aElement);
  if (redirectedFocus) {
    return CheckIfFocusable(redirectedFocus, aFlags);
  }

  nsCOMPtr<Document> doc = aElement->GetComposedDoc();
  // can't focus elements that are not in documents
  if (!doc) {
    LOGCONTENT("Cannot focus %s because content not in document", aElement)
    return nullptr;
  }

  // Make sure that our frames are up to date while ensuring the presshell is
  // also initialized in case we come from a script calling focus() early.
  mEventHandlingNeedsFlush = false;
  doc->FlushPendingNotifications(FlushType::EnsurePresShellInitAndFrames);

  nsIPresShell* shell = doc->GetShell();
  if (!shell) return nullptr;

  // the root content can always be focused,
  // except in userfocusignored context.
  if (aElement == doc->GetRootElement()) {
    return nsContentUtils::IsUserFocusIgnored(aElement) ? nullptr : aElement;
  }

  // cannot focus content in print preview mode. Only the root can be focused.
  nsPresContext* presContext = shell->GetPresContext();
  if (presContext &&
      presContext->Type() == nsPresContext::eContext_PrintPreview) {
    LOGCONTENT("Cannot focus %s while in print preview", aElement)
    return nullptr;
  }

  nsIFrame* frame = aElement->GetPrimaryFrame();
  if (!frame) {
    LOGCONTENT("Cannot focus %s as it has no frame", aElement)
    return nullptr;
  }

  if (aElement->IsHTMLElement(nsGkAtoms::area)) {
    // HTML areas do not have their own frame, and the img frame we get from
    // GetPrimaryFrame() is not relevant as to whether it is focusable or
    // not, so we have to do all the relevant checks manually for them.
    return frame->IsVisibleConsideringAncestors() && aElement->IsFocusable()
               ? aElement
               : nullptr;
  }

  // if this is a child frame content node, check if it is visible and
  // call the content node's IsFocusable method instead of the frame's
  // IsFocusable method. This skips checking the style system and ensures that
  // offscreen browsers can still be focused.
  Document* subdoc = doc->GetSubDocumentFor(aElement);
  if (subdoc && IsWindowVisible(subdoc->GetWindow())) {
    const nsStyleUI* ui = frame->StyleUI();
    int32_t tabIndex = (ui->mUserFocus == StyleUserFocus::Ignore ||
                        ui->mUserFocus == StyleUserFocus::None)
                           ? -1
                           : 0;
    return aElement->IsFocusable(&tabIndex, aFlags & FLAG_BYMOUSE) ? aElement
                                                                   : nullptr;
  }

  return frame->IsFocusable(nullptr, aFlags & FLAG_BYMOUSE) ? aElement
                                                            : nullptr;
}

bool nsFocusManager::Blur(nsPIDOMWindowOuter* aWindowToClear,
                          nsPIDOMWindowOuter* aAncestorWindowToFocus,
                          bool aIsLeavingDocument, bool aAdjustWidgets,
                          nsIContent* aContentToFocus) {
  LOGFOCUS(("<<Blur begin>>"));

  // hold a reference to the focused content, which may be null
  RefPtr<Element> element = mFocusedElement;
  if (element) {
    if (!element->IsInComposedDoc()) {
      mFocusedElement = nullptr;
      return true;
    }
    if (element == mFirstBlurEvent) return true;
  }

  // hold a reference to the focused window
  nsCOMPtr<nsPIDOMWindowOuter> window = mFocusedWindow;
  if (!window) {
    mFocusedElement = nullptr;
    return true;
  }

  nsCOMPtr<nsIDocShell> docShell = window->GetDocShell();
  if (!docShell) {
    mFocusedWindow = nullptr;
    mFocusedElement = nullptr;
    return true;
  }

  // Keep a ref to presShell since dispatching the DOM event may cause
  // the document to be destroyed.
  nsCOMPtr<nsIPresShell> presShell = docShell->GetPresShell();
  if (!presShell) {
    mFocusedElement = nullptr;
    mFocusedWindow = nullptr;
    return true;
  }

  bool clearFirstBlurEvent = false;
  if (!mFirstBlurEvent) {
    mFirstBlurEvent = element;
    clearFirstBlurEvent = true;
  }

  nsPresContext* focusedPresContext =
      mActiveWindow ? presShell->GetPresContext() : nullptr;
  IMEStateManager::OnChangeFocus(focusedPresContext, nullptr,
                                 GetFocusMoveActionCause(0));

  // now adjust the actual focus, by clearing the fields in the focus manager
  // and in the window.
  mFocusedElement = nullptr;
  bool shouldShowFocusRing = window->ShouldShowFocusRing();
  if (aWindowToClear) aWindowToClear->SetFocusedElement(nullptr);

  LOGCONTENT("Element %s has been blurred", element.get());

  // Don't fire blur event on the root content which isn't editable.
  bool sendBlurEvent =
      element && element->IsInComposedDoc() && !IsNonFocusableRoot(element);
  if (element) {
    if (sendBlurEvent) {
      NotifyFocusStateChange(element, aContentToFocus, shouldShowFocusRing,
                             false);
    }

    // if an object/plug-in/remote browser is being blurred, move the system
    // focus to the parent window, otherwise events will still get fired at the
    // plugin. But don't do this if we are blurring due to the window being
    // lowered, otherwise, the parent window can get raised again.
    if (mActiveWindow) {
      nsIFrame* contentFrame = element->GetPrimaryFrame();
      nsIObjectFrame* objectFrame = do_QueryFrame(contentFrame);
      if (aAdjustWidgets && objectFrame && !sTestMode) {
        if (XRE_IsContentProcess()) {
          // set focus to the top level window via the chrome process.
          nsCOMPtr<nsITabChild> tabChild = docShell->GetTabChild();
          if (tabChild) {
            static_cast<TabChild*>(tabChild.get())
                ->SendDispatchFocusToTopLevelWindow();
          }
        } else {
          // note that the presshell's widget is being retrieved here, not the
          // one for the object frame.
          nsViewManager* vm = presShell->GetViewManager();
          if (vm) {
            nsCOMPtr<nsIWidget> widget;
            vm->GetRootWidget(getter_AddRefs(widget));
            if (widget) {
              // set focus to the top level window but don't raise it.
              widget->SetFocus(false);
            }
          }
        }
      }
    }

    // if the object being blurred is a remote browser, deactivate remote
    // content
    if (TabParent* remote = TabParent::GetFrom(element)) {
      remote->Deactivate();
      LOGFOCUS(("Remote browser deactivated"));
    }
  }

  bool result = true;
  if (sendBlurEvent) {
    // if there is an active window, update commands. If there isn't an active
    // window, then this was a blur caused by the active window being lowered,
    // so there is no need to update the commands
    if (mActiveWindow)
      window->UpdateCommands(NS_LITERAL_STRING("focus"), nullptr, 0);

    SendFocusOrBlurEvent(eBlur, presShell, element->GetComposedDoc(), element,
                         1, false, false, aContentToFocus);
  }

  // if we are leaving the document or the window was lowered, make the caret
  // invisible.
  if (aIsLeavingDocument || !mActiveWindow) {
    SetCaretVisible(presShell, false, nullptr);
  }

  RefPtr<AccessibleCaretEventHub> eventHub =
      presShell->GetAccessibleCaretEventHub();
  if (eventHub) {
    eventHub->NotifyBlur(aIsLeavingDocument || !mActiveWindow);
  }

  // at this point, it is expected that this window will be still be
  // focused, but the focused element will be null, as it was cleared before
  // the event. If this isn't the case, then something else was focused during
  // the blur event above and we should just return. However, if
  // aIsLeavingDocument is set, a new document is desired, so make sure to
  // blur the document and window.
  if (mFocusedWindow != window ||
      (mFocusedElement != nullptr && !aIsLeavingDocument)) {
    result = false;
  } else if (aIsLeavingDocument) {
    window->TakeFocus(false, 0);

    // clear the focus so that the ancestor frame hierarchy is in the correct
    // state. Pass true because aAncestorWindowToFocus is thought to be
    // focused at this point.
    if (aAncestorWindowToFocus)
      aAncestorWindowToFocus->SetFocusedElement(nullptr, 0, true);

    SetFocusedWindowInternal(nullptr);
    mFocusedElement = nullptr;

    // pass 1 for the focus method when calling SendFocusOrBlurEvent just so
    // that the check is made for suppressed documents. Check to ensure that
    // the document isn't null in case someone closed it during the blur above
    Document* doc = window->GetExtantDoc();
    if (doc)
      SendFocusOrBlurEvent(eBlur, presShell, doc, ToSupports(doc), 1, false);
    if (mFocusedWindow == nullptr)
      SendFocusOrBlurEvent(eBlur, presShell, doc,
                           window->GetCurrentInnerWindow(), 1, false);

    // check if a different window was focused
    result = (mFocusedWindow == nullptr && mActiveWindow);
  } else if (mActiveWindow) {
    // Otherwise, the blur of the element without blurring the document
    // occurred normally. Call UpdateCaret to redisplay the caret at the right
    // location within the document. This is needed to ensure that the caret
    // used for caret browsing is made visible again when an input field is
    // blurred.
    UpdateCaret(false, true, nullptr);
  }

  if (clearFirstBlurEvent) mFirstBlurEvent = nullptr;

  return result;
}

void nsFocusManager::Focus(nsPIDOMWindowOuter* aWindow, Element* aElement,
                           uint32_t aFlags, bool aIsNewDocument,
                           bool aFocusChanged, bool aWindowRaised,
                           bool aAdjustWidgets, nsIContent* aContentLostFocus) {
  LOGFOCUS(("<<Focus begin>>"));

  if (!aWindow) return;

  if (aElement && (aElement == mFirstFocusEvent || aElement == mFirstBlurEvent))
    return;

  // Keep a reference to the presShell since dispatching the DOM event may
  // cause the document to be destroyed.
  nsCOMPtr<nsIDocShell> docShell = aWindow->GetDocShell();
  if (!docShell) return;

  nsCOMPtr<nsIPresShell> presShell = docShell->GetPresShell();
  if (!presShell) return;

  // If the focus actually changed, set the focus method (mouse, keyboard, etc).
  // Otherwise, just get the current focus method and use that. This ensures
  // that the method is set during the document and window focus events.
  uint32_t focusMethod =
      aFocusChanged ? aFlags & FOCUSMETHODANDRING_MASK
                    : aWindow->GetFocusMethod() | (aFlags & FLAG_SHOWRING);

  if (!IsWindowVisible(aWindow)) {
    // if the window isn't visible, for instance because it is a hidden tab,
    // update the current focus and scroll it into view but don't do anything
    // else
    if (CheckIfFocusable(aElement, aFlags)) {
      aWindow->SetFocusedElement(aElement, focusMethod);
      if (aFocusChanged) ScrollIntoView(presShell, aElement, aFlags);
    }
    return;
  }

  bool clearFirstFocusEvent = false;
  if (!mFirstFocusEvent) {
    mFirstFocusEvent = aElement;
    clearFirstFocusEvent = true;
  }

  LOGCONTENT("Element %s has been focused", aElement);

  if (MOZ_LOG_TEST(gFocusLog, LogLevel::Debug)) {
    Document* docm = aWindow->GetExtantDoc();
    if (docm) {
      LOGCONTENT(" from %s", docm->GetRootElement());
    }
    LOGFOCUS((" [Newdoc: %d FocusChanged: %d Raised: %d Flags: %x]",
              aIsNewDocument, aFocusChanged, aWindowRaised, aFlags));
  }

  if (aIsNewDocument) {
    // if this is a new document, update the parent chain of frames so that
    // focus can be traversed from the top level down to the newly focused
    // window.
    AdjustWindowFocus(aWindow, false);
  }

  // indicate that the window has taken focus.
  if (aWindow->TakeFocus(true, focusMethod)) aIsNewDocument = true;

  SetFocusedWindowInternal(aWindow);

  // Update the system focus by focusing the root widget.  But avoid this
  // if 1) aAdjustWidgets is false or 2) aElement is a plugin that has its
  // own widget and is either already focused or is about to be focused.
  nsCOMPtr<nsIWidget> objectFrameWidget;
  if (aElement) {
    nsIFrame* contentFrame = aElement->GetPrimaryFrame();
    nsIObjectFrame* objectFrame = do_QueryFrame(contentFrame);
    if (objectFrame) objectFrameWidget = objectFrame->GetWidget();
  }
  if (aAdjustWidgets && !objectFrameWidget && !sTestMode) {
    nsViewManager* vm = presShell->GetViewManager();
    if (vm) {
      nsCOMPtr<nsIWidget> widget;
      vm->GetRootWidget(getter_AddRefs(widget));
      if (widget) widget->SetFocus(false);
    }
  }

  // if switching to a new document, first fire the focus event on the
  // document and then the window.
  if (aIsNewDocument) {
    Document* doc = aWindow->GetExtantDoc();
    // The focus change should be notified to IMEStateManager from here if
    // the focused element is a designMode editor since any content won't
    // receive focus event.
    if (doc && doc->HasFlag(NODE_IS_EDITABLE)) {
      IMEStateManager::OnChangeFocus(presShell->GetPresContext(), nullptr,
                                     GetFocusMoveActionCause(aFlags));
    }
    if (doc) {
      SendFocusOrBlurEvent(eFocus, presShell, doc, ToSupports(doc),
                           aFlags & FOCUSMETHOD_MASK, aWindowRaised);
    }
    if (mFocusedWindow == aWindow && mFocusedElement == nullptr) {
      SendFocusOrBlurEvent(eFocus, presShell, doc,
                           aWindow->GetCurrentInnerWindow(),
                           aFlags & FOCUSMETHOD_MASK, aWindowRaised);
    }
  }

  // check to ensure that the element is still focusable, and that nothing
  // else was focused during the events above.
  if (CheckIfFocusable(aElement, aFlags) && mFocusedWindow == aWindow &&
      mFocusedElement == nullptr) {
    mFocusedElement = aElement;

    nsIContent* focusedNode = aWindow->GetFocusedElement();
    bool isRefocus = focusedNode && focusedNode->IsEqualNode(aElement);

    aWindow->SetFocusedElement(aElement, focusMethod);

    // if the focused element changed, scroll it into view
    if (aElement && aFocusChanged) {
      ScrollIntoView(presShell, aElement, aFlags);
    }

    bool sendFocusEvent = aElement && aElement->IsInComposedDoc() &&
                          !IsNonFocusableRoot(aElement);
    nsPresContext* presContext = presShell->GetPresContext();
    if (sendFocusEvent) {
      NotifyFocusStateChange(aElement, nullptr, aWindow->ShouldShowFocusRing(),
                             true);

      // if this is an object/plug-in/remote browser, focus its widget.  Note
      // that we might no longer be in the same document, due to the events we
      // fired above when aIsNewDocument.
      if (presShell->GetDocument() == aElement->GetComposedDoc()) {
        if (aAdjustWidgets && objectFrameWidget && !sTestMode)
          objectFrameWidget->SetFocus(false);

        // if the object being focused is a remote browser, activate remote
        // content
        if (TabParent* remote = TabParent::GetFrom(aElement)) {
          remote->Activate();
          LOGFOCUS(("Remote browser activated"));
        }
      }

      IMEStateManager::OnChangeFocus(presContext, aElement,
                                     GetFocusMoveActionCause(aFlags));

      // as long as this focus wasn't because a window was raised, update the
      // commands
      // XXXndeakin P2 someone could adjust the focus during the update
      if (!aWindowRaised)
        aWindow->UpdateCommands(NS_LITERAL_STRING("focus"), nullptr, 0);

      SendFocusOrBlurEvent(eFocus, presShell, aElement->GetComposedDoc(),
                           aElement, aFlags & FOCUSMETHOD_MASK, aWindowRaised,
                           isRefocus, aContentLostFocus);
    } else {
      IMEStateManager::OnChangeFocus(presContext, nullptr,
                                     GetFocusMoveActionCause(aFlags));
      if (!aWindowRaised) {
        aWindow->UpdateCommands(NS_LITERAL_STRING("focus"), nullptr, 0);
      }
    }
  } else {
    // If the window focus event (fired above when aIsNewDocument) caused
    // the plugin not to be focusable, update the system focus by focusing
    // the root widget.
    if (aAdjustWidgets && objectFrameWidget && mFocusedWindow == aWindow &&
        mFocusedElement == nullptr && !sTestMode) {
      nsViewManager* vm = presShell->GetViewManager();
      if (vm) {
        nsCOMPtr<nsIWidget> widget;
        vm->GetRootWidget(getter_AddRefs(widget));
        if (widget) widget->SetFocus(false);
      }
    }

    if (!mFocusedElement) {
      // When there is no focused element, IMEStateManager needs to adjust IME
      // enabled state with the document.
      nsPresContext* presContext = presShell->GetPresContext();
      IMEStateManager::OnChangeFocus(presContext, nullptr,
                                     GetFocusMoveActionCause(aFlags));
    }

    if (!aWindowRaised)
      aWindow->UpdateCommands(NS_LITERAL_STRING("focus"), nullptr, 0);
  }

  // update the caret visibility and position to match the newly focused
  // element. However, don't update the position if this was a focus due to a
  // mouse click as the selection code would already have moved the caret as
  // needed. If this is a different document than was focused before, also
  // update the caret's visibility. If this is the same document, the caret
  // visibility should be the same as before so there is no need to update it.
  if (mFocusedElement == aElement)
    UpdateCaret(aFocusChanged && !(aFlags & FLAG_BYMOUSE), aIsNewDocument,
                mFocusedElement);

  if (clearFirstFocusEvent) mFirstFocusEvent = nullptr;
}

class FocusBlurEvent : public Runnable {
 public:
  FocusBlurEvent(nsISupports* aTarget, EventMessage aEventMessage,
                 nsPresContext* aContext, bool aWindowRaised, bool aIsRefocus,
                 EventTarget* aRelatedTarget)
      : mozilla::Runnable("FocusBlurEvent"),
        mTarget(aTarget),
        mContext(aContext),
        mEventMessage(aEventMessage),
        mWindowRaised(aWindowRaised),
        mIsRefocus(aIsRefocus),
        mRelatedTarget(aRelatedTarget) {}

  NS_IMETHOD Run() override {
    InternalFocusEvent event(true, mEventMessage);
    event.mFlags.mBubbles = false;
    event.mFlags.mCancelable = false;
    event.mFromRaise = mWindowRaised;
    event.mIsRefocus = mIsRefocus;
    event.mRelatedTarget = mRelatedTarget;
    return EventDispatcher::Dispatch(mTarget, mContext, &event);
  }

  nsCOMPtr<nsISupports> mTarget;
  RefPtr<nsPresContext> mContext;
  EventMessage mEventMessage;
  bool mWindowRaised;
  bool mIsRefocus;
  nsCOMPtr<EventTarget> mRelatedTarget;
};

class FocusInOutEvent : public Runnable {
 public:
  FocusInOutEvent(nsISupports* aTarget, EventMessage aEventMessage,
                  nsPresContext* aContext,
                  nsPIDOMWindowOuter* aOriginalFocusedWindow,
                  nsIContent* aOriginalFocusedContent,
                  EventTarget* aRelatedTarget)
      : mozilla::Runnable("FocusInOutEvent"),
        mTarget(aTarget),
        mContext(aContext),
        mEventMessage(aEventMessage),
        mOriginalFocusedWindow(aOriginalFocusedWindow),
        mOriginalFocusedContent(aOriginalFocusedContent),
        mRelatedTarget(aRelatedTarget) {}

  NS_IMETHOD Run() override {
    nsCOMPtr<nsIContent> originalWindowFocus =
        mOriginalFocusedWindow ? mOriginalFocusedWindow->GetFocusedElement()
                               : nullptr;
    // Blink does not check that focus is the same after blur, but WebKit does.
    // Opt to follow Blink's behavior (see bug 687787).
    if (mEventMessage == eFocusOut ||
        originalWindowFocus == mOriginalFocusedContent) {
      InternalFocusEvent event(true, mEventMessage);
      event.mFlags.mBubbles = true;
      event.mFlags.mCancelable = false;
      event.mRelatedTarget = mRelatedTarget;
      return EventDispatcher::Dispatch(mTarget, mContext, &event);
    }
    return NS_OK;
  }

  nsCOMPtr<nsISupports> mTarget;
  RefPtr<nsPresContext> mContext;
  EventMessage mEventMessage;
  nsCOMPtr<nsPIDOMWindowOuter> mOriginalFocusedWindow;
  nsCOMPtr<nsIContent> mOriginalFocusedContent;
  nsCOMPtr<EventTarget> mRelatedTarget;
};

static Document* GetDocumentHelper(EventTarget* aTarget) {
  nsCOMPtr<nsINode> node = do_QueryInterface(aTarget);
  if (!node) {
    nsCOMPtr<nsPIDOMWindowInner> win = do_QueryInterface(aTarget);
    return win ? win->GetExtantDoc() : nullptr;
  }

  return node->OwnerDoc();
}

void nsFocusManager::FireFocusInOrOutEvent(
    EventMessage aEventMessage, nsIPresShell* aPresShell, nsISupports* aTarget,
    nsPIDOMWindowOuter* aCurrentFocusedWindow,
    nsIContent* aCurrentFocusedContent, EventTarget* aRelatedTarget) {
  NS_ASSERTION(aEventMessage == eFocusIn || aEventMessage == eFocusOut,
               "Wrong event type for FireFocusInOrOutEvent");

  nsContentUtils::AddScriptRunner(new FocusInOutEvent(
      aTarget, aEventMessage, aPresShell->GetPresContext(),
      aCurrentFocusedWindow, aCurrentFocusedContent, aRelatedTarget));
}

void nsFocusManager::SendFocusOrBlurEvent(
    EventMessage aEventMessage, nsIPresShell* aPresShell, Document* aDocument,
    nsISupports* aTarget, uint32_t aFocusMethod, bool aWindowRaised,
    bool aIsRefocus, EventTarget* aRelatedTarget) {
  NS_ASSERTION(aEventMessage == eFocus || aEventMessage == eBlur,
               "Wrong event type for SendFocusOrBlurEvent");

  nsCOMPtr<EventTarget> eventTarget = do_QueryInterface(aTarget);
  nsCOMPtr<Document> eventTargetDoc = GetDocumentHelper(eventTarget);
  nsCOMPtr<Document> relatedTargetDoc = GetDocumentHelper(aRelatedTarget);

  // set aRelatedTarget to null if it's not in the same document as eventTarget
  if (eventTargetDoc != relatedTargetDoc) {
    aRelatedTarget = nullptr;
  }

  bool dontDispatchEvent =
      eventTargetDoc && nsContentUtils::IsUserFocusIgnored(eventTargetDoc);

  if (!dontDispatchEvent && aDocument && aDocument->EventHandlingSuppressed()) {
    for (uint32_t i = mDelayedBlurFocusEvents.Length(); i > 0; --i) {
      // if this event was already queued, remove it and append it to the end
      if (mDelayedBlurFocusEvents[i - 1].mEventMessage == aEventMessage &&
          mDelayedBlurFocusEvents[i - 1].mPresShell == aPresShell &&
          mDelayedBlurFocusEvents[i - 1].mDocument == aDocument &&
          mDelayedBlurFocusEvents[i - 1].mTarget == eventTarget &&
          mDelayedBlurFocusEvents[i - 1].mRelatedTarget == aRelatedTarget) {
        mDelayedBlurFocusEvents.RemoveElementAt(i - 1);
      }
    }

    mDelayedBlurFocusEvents.AppendElement(nsDelayedBlurOrFocusEvent(
        aEventMessage, aPresShell, aDocument, eventTarget, aRelatedTarget));
    return;
  }

  // If mDelayedBlurFocusEvents queue is not empty, check if there are events
  // that belongs to this doc, if yes, fire them first.
  if (aDocument && !aDocument->EventHandlingSuppressed() &&
      mDelayedBlurFocusEvents.Length()) {
    FireDelayedEvents(aDocument);
  }

  FireFocusOrBlurEvent(aEventMessage, aPresShell, aTarget, aWindowRaised,
                       aIsRefocus, aRelatedTarget);
}

void nsFocusManager::FireFocusOrBlurEvent(EventMessage aEventMessage,
                                          nsIPresShell* aPresShell,
                                          nsISupports* aTarget,
                                          bool aWindowRaised, bool aIsRefocus,
                                          EventTarget* aRelatedTarget) {
  nsCOMPtr<EventTarget> eventTarget = do_QueryInterface(aTarget);
  nsCOMPtr<Document> eventTargetDoc = GetDocumentHelper(eventTarget);
  nsCOMPtr<nsPIDOMWindowOuter> currentWindow = mFocusedWindow;
  nsCOMPtr<nsPIDOMWindowInner> targetWindow = do_QueryInterface(aTarget);
  nsCOMPtr<Document> targetDocument = do_QueryInterface(aTarget);
  nsCOMPtr<nsIContent> currentFocusedContent =
      currentWindow ? currentWindow->GetFocusedElement() : nullptr;

  bool dontDispatchEvent =
      eventTargetDoc && nsContentUtils::IsUserFocusIgnored(eventTargetDoc);

#ifdef ACCESSIBILITY
  nsAccessibilityService* accService = GetAccService();
  if (accService) {
    if (aEventMessage == eFocus) {
      accService->NotifyOfDOMFocus(aTarget);
    } else {
      accService->NotifyOfDOMBlur(aTarget);
    }
  }
#endif

  if (!dontDispatchEvent) {
    nsContentUtils::AddScriptRunner(
        new FocusBlurEvent(aTarget, aEventMessage, aPresShell->GetPresContext(),
                           aWindowRaised, aIsRefocus, aRelatedTarget));

    // Check that the target is not a window or document before firing
    // focusin/focusout. Other browsers do not fire focusin/focusout on window,
    // despite being required in the spec, so follow their behavior.
    //
    // As for document, we should not even fire focus/blur, but until then, we
    // need this check. targetDocument should be removed once bug 1228802 is
    // resolved.
    if (!targetWindow && !targetDocument) {
      EventMessage focusInOrOutMessage =
          aEventMessage == eFocus ? eFocusIn : eFocusOut;
      FireFocusInOrOutEvent(focusInOrOutMessage, aPresShell, aTarget,
                            currentWindow, currentFocusedContent,
                            aRelatedTarget);
    }
  }
}

void nsFocusManager::ScrollIntoView(nsIPresShell* aPresShell,
                                    nsIContent* aContent, uint32_t aFlags) {
  // if the noscroll flag isn't set, scroll the newly focused element into view
  if (!(aFlags & FLAG_NOSCROLL))
    aPresShell->ScrollContentIntoView(
        aContent,
        nsIPresShell::ScrollAxis(nsIPresShell::SCROLL_MINIMUM,
                                 nsIPresShell::SCROLL_IF_NOT_VISIBLE),
        nsIPresShell::ScrollAxis(nsIPresShell::SCROLL_MINIMUM,
                                 nsIPresShell::SCROLL_IF_NOT_VISIBLE),
        nsIPresShell::SCROLL_OVERFLOW_HIDDEN);
}

void nsFocusManager::RaiseWindow(nsPIDOMWindowOuter* aWindow) {
  // don't raise windows that are already raised or are in the process of
  // being lowered
  if (!aWindow || aWindow == mActiveWindow || aWindow == mWindowBeingLowered)
    return;

  if (sTestMode) {
    // In test mode, emulate the existing window being lowered and the new
    // window being raised. This happens in a separate runnable to avoid
    // touching multiple windows in the current runnable.
    nsCOMPtr<nsPIDOMWindowOuter> active(mActiveWindow);
    nsCOMPtr<nsPIDOMWindowOuter> window(aWindow);
    RefPtr<nsFocusManager> self(this);
    NS_DispatchToCurrentThread(NS_NewRunnableFunction(
        "nsFocusManager::RaiseWindow", [self, active, window]() -> void {
          if (active) {
            self->WindowLowered(active);
          }
          self->WindowRaised(window);
        }));
    return;
  }

#if defined(XP_WIN)
  // Windows would rather we focus the child widget, otherwise, the toplevel
  // widget will always end up being focused. Fortunately, focusing the child
  // widget will also have the effect of raising the window this widget is in.
  // But on other platforms, we can just focus the toplevel widget to raise
  // the window.
  nsCOMPtr<nsPIDOMWindowOuter> childWindow;
  GetFocusedDescendant(aWindow, eIncludeAllDescendants,
                       getter_AddRefs(childWindow));
  if (!childWindow) childWindow = aWindow;

  nsCOMPtr<nsIDocShell> docShell = aWindow->GetDocShell();
  if (!docShell) return;

  nsCOMPtr<nsIPresShell> presShell = docShell->GetPresShell();
  if (!presShell) return;

  nsViewManager* vm = presShell->GetViewManager();
  if (vm) {
    nsCOMPtr<nsIWidget> widget;
    vm->GetRootWidget(getter_AddRefs(widget));
    if (widget) widget->SetFocus(true);
  }
#else
  nsCOMPtr<nsIBaseWindow> treeOwnerAsWin =
      do_QueryInterface(aWindow->GetDocShell());
  if (treeOwnerAsWin) {
    nsCOMPtr<nsIWidget> widget;
    treeOwnerAsWin->GetMainWidget(getter_AddRefs(widget));
    if (widget) widget->SetFocus(true);
  }
#endif
}

void nsFocusManager::UpdateCaretForCaretBrowsingMode() {
  UpdateCaret(false, true, mFocusedElement);
}

void nsFocusManager::UpdateCaret(bool aMoveCaretToFocus, bool aUpdateVisibility,
                                 nsIContent* aContent) {
  LOGFOCUS(("Update Caret: %d %d", aMoveCaretToFocus, aUpdateVisibility));

  if (!mFocusedWindow) return;

  // this is called when a document is focused or when the caretbrowsing
  // preference is changed
  nsCOMPtr<nsIDocShell> focusedDocShell = mFocusedWindow->GetDocShell();
  if (!focusedDocShell) {
    return;
  }

  if (focusedDocShell->ItemType() == nsIDocShellTreeItem::typeChrome) {
    return;  // Never browse with caret in chrome
  }

  bool browseWithCaret = Preferences::GetBool("accessibility.browsewithcaret");

  nsCOMPtr<nsIPresShell> presShell = focusedDocShell->GetPresShell();
  if (!presShell) return;

  // If this is an editable document which isn't contentEditable, or a
  // contentEditable document and the node to focus is contentEditable,
  // return, so that we don't mess with caret visibility.
  bool isEditable = false;
  focusedDocShell->GetEditable(&isEditable);

  if (isEditable) {
    nsCOMPtr<nsIHTMLDocument> doc = do_QueryInterface(presShell->GetDocument());

    bool isContentEditableDoc =
        doc && doc->GetEditingState() == nsIHTMLDocument::eContentEditable;

    bool isFocusEditable = aContent && aContent->HasFlag(NODE_IS_EDITABLE);
    if (!isContentEditableDoc || isFocusEditable) return;
  }

  if (!isEditable && aMoveCaretToFocus) MoveCaretToFocus(presShell, aContent);

  if (!aUpdateVisibility) return;

  // XXXndeakin this doesn't seem right. It should be checking for this only
  // on the nearest ancestor frame which is a chrome frame. But this is
  // what the existing code does, so just leave it for now.
  if (!browseWithCaret) {
    nsCOMPtr<Element> docElement = mFocusedWindow->GetFrameElementInternal();
    if (docElement)
      browseWithCaret =
          docElement->AttrValueIs(kNameSpaceID_None, nsGkAtoms::showcaret,
                                  NS_LITERAL_STRING("true"), eCaseMatters);
  }

  SetCaretVisible(presShell, browseWithCaret, aContent);
}

void nsFocusManager::MoveCaretToFocus(nsIPresShell* aPresShell,
                                      nsIContent* aContent) {
  nsCOMPtr<Document> doc = aPresShell->GetDocument();
  if (doc) {
    RefPtr<nsFrameSelection> frameSelection = aPresShell->FrameSelection();
    RefPtr<Selection> domSelection =
        frameSelection->GetSelection(SelectionType::eNormal);
    if (domSelection) {
      // First clear the selection. This way, if there is no currently focused
      // content, the selection will just be cleared.
      domSelection->RemoveAllRanges(IgnoreErrors());
      if (aContent) {
        ErrorResult rv;
        RefPtr<nsRange> newRange = doc->CreateRange(rv);
        if (NS_WARN_IF(rv.Failed())) {
          rv.SuppressException();
          return;
        }

        // Set the range to the start of the currently focused node
        // Make sure it's collapsed
        newRange->SelectNodeContents(*aContent, IgnoreErrors());

        if (!aContent->GetFirstChild() ||
            aContent->IsNodeOfType(nsINode::eHTML_FORM_CONTROL)) {
          // If current focus node is a leaf, set range to before the
          // node by using the parent as a container.
          // This prevents it from appearing as selected.
          newRange->SetStartBefore(*aContent, IgnoreErrors());
          newRange->SetEndBefore(*aContent, IgnoreErrors());
        }
        domSelection->AddRange(*newRange, IgnoreErrors());
        domSelection->CollapseToStart(IgnoreErrors());
      }
    }
  }
}

nsresult nsFocusManager::SetCaretVisible(nsIPresShell* aPresShell,
                                         bool aVisible, nsIContent* aContent) {
  // When browsing with caret, make sure caret is visible after new focus
  // Return early if there is no caret. This can happen for the testcase
  // for bug 308025 where a window is closed in a blur handler.
  RefPtr<nsCaret> caret = aPresShell->GetCaret();
  if (!caret) return NS_OK;

  bool caretVisible = caret->IsVisible();
  if (!aVisible && !caretVisible) return NS_OK;

  RefPtr<nsFrameSelection> frameSelection;
  if (aContent) {
    NS_ASSERTION(aContent->GetComposedDoc() == aPresShell->GetDocument(),
                 "Wrong document?");
    nsIFrame* focusFrame = aContent->GetPrimaryFrame();
    if (focusFrame) frameSelection = focusFrame->GetFrameSelection();
  }

  RefPtr<nsFrameSelection> docFrameSelection = aPresShell->FrameSelection();

  if (docFrameSelection && caret &&
      (frameSelection == docFrameSelection || !aContent)) {
    Selection* domSelection =
        docFrameSelection->GetSelection(SelectionType::eNormal);
    if (domSelection) {
      nsCOMPtr<nsISelectionController> selCon(do_QueryInterface(aPresShell));
      if (!selCon) {
        return NS_ERROR_FAILURE;
      }
      // First, hide the caret to prevent attempting to show it in
      // SetCaretDOMSelection
      selCon->SetCaretEnabled(false);

      // Caret must blink on non-editable elements
      caret->SetIgnoreUserModify(true);
      // Tell the caret which selection to use
      caret->SetSelection(domSelection);

      // In content, we need to set the caret. The only special case is edit
      // fields, which have a different frame selection from the document.
      // They will take care of making the caret visible themselves.

      selCon->SetCaretReadOnly(false);
      selCon->SetCaretEnabled(aVisible);
    }
  }

  return NS_OK;
}

nsresult nsFocusManager::GetSelectionLocation(Document* aDocument,
                                              nsIPresShell* aPresShell,
                                              nsIContent** aStartContent,
                                              nsIContent** aEndContent) {
  *aStartContent = *aEndContent = nullptr;
  nsPresContext* presContext = aPresShell->GetPresContext();
  NS_ASSERTION(presContext, "mPresContent is null!!");

  RefPtr<nsFrameSelection> frameSelection = aPresShell->FrameSelection();

  RefPtr<Selection> domSelection;
  if (frameSelection) {
    domSelection = frameSelection->GetSelection(SelectionType::eNormal);
  }

  bool isCollapsed = false;
  nsCOMPtr<nsIContent> startContent, endContent;
  uint32_t startOffset = 0;
  if (domSelection) {
    isCollapsed = domSelection->IsCollapsed();
    RefPtr<nsRange> domRange = domSelection->GetRangeAt(0);
    if (domRange) {
      nsCOMPtr<nsINode> startNode = domRange->GetStartContainer();
      nsCOMPtr<nsINode> endNode = domRange->GetEndContainer();
      startOffset = domRange->StartOffset();

      nsIContent* childContent = nullptr;

      startContent = do_QueryInterface(startNode);
      if (startContent && startContent->IsElement()) {
        childContent = startContent->GetChildAt_Deprecated(startOffset);
        if (childContent) {
          startContent = childContent;
        }
      }

      endContent = do_QueryInterface(endNode);
      if (endContent && endContent->IsElement()) {
        uint32_t endOffset = domRange->EndOffset();
        childContent = endContent->GetChildAt_Deprecated(endOffset);
        if (childContent) {
          endContent = childContent;
        }
      }
    }
  } else {
    return NS_ERROR_INVALID_ARG;
  }

  nsIFrame* startFrame = nullptr;
  if (startContent) {
    startFrame = startContent->GetPrimaryFrame();
    if (isCollapsed) {
      // Next check to see if our caret is at the very end of a node
      // If so, the caret is actually sitting in front of the next
      // logical frame's primary node - so for this case we need to
      // change caretContent to that node.

      if (startContent->NodeType() == nsINode::TEXT_NODE) {
        nsAutoString nodeValue;
        startContent->GetAsText()->AppendTextTo(nodeValue);

        bool isFormControl =
            startContent->IsNodeOfType(nsINode::eHTML_FORM_CONTROL);

        if (nodeValue.Length() == startOffset && !isFormControl &&
            startContent != aDocument->GetRootElement()) {
          // Yes, indeed we were at the end of the last node
          nsCOMPtr<nsIFrameEnumerator> frameTraversal;
          nsresult rv = NS_NewFrameTraversal(getter_AddRefs(frameTraversal),
                                             presContext, startFrame, eLeaf,
                                             false,  // aVisual
                                             false,  // aLockInScrollView
                                             true,   // aFollowOOFs
                                             false   // aSkipPopupChecks
          );
          NS_ENSURE_SUCCESS(rv, rv);

          nsIFrame* newCaretFrame = nullptr;
          nsCOMPtr<nsIContent> newCaretContent = startContent;
          bool endOfSelectionInStartNode(startContent == endContent);
          do {
            // Continue getting the next frame until the primary content for the
            // frame we are on changes - we don't want to be stuck in the same
            // place
            frameTraversal->Next();
            newCaretFrame =
                static_cast<nsIFrame*>(frameTraversal->CurrentItem());
            if (nullptr == newCaretFrame) break;
            newCaretContent = newCaretFrame->GetContent();
          } while (!newCaretContent || newCaretContent == startContent);

          if (newCaretFrame && newCaretContent) {
            // If the caret is exactly at the same position of the new frame,
            // then we can use the newCaretFrame and newCaretContent for our
            // position
            nsRect caretRect;
            nsIFrame* frame = nsCaret::GetGeometry(domSelection, &caretRect);
            if (frame) {
              nsPoint caretWidgetOffset;
              nsIWidget* widget = frame->GetNearestWidget(caretWidgetOffset);
              caretRect.MoveBy(caretWidgetOffset);
              nsPoint newCaretOffset;
              nsIWidget* newCaretWidget =
                  newCaretFrame->GetNearestWidget(newCaretOffset);
              if (widget == newCaretWidget && caretRect.y == newCaretOffset.y &&
                  caretRect.x == newCaretOffset.x) {
                // The caret is at the start of the new element.
                startFrame = newCaretFrame;
                startContent = newCaretContent;
                if (endOfSelectionInStartNode) {
                  endContent = newCaretContent;  // Ensure end of selection is
                                                 // not before start
                }
              }
            }
          }
        }
      }
    }
  }

  *aStartContent = startContent;
  *aEndContent = endContent;
  NS_IF_ADDREF(*aStartContent);
  NS_IF_ADDREF(*aEndContent);

  return NS_OK;
}

nsresult nsFocusManager::DetermineElementToMoveFocus(
    nsPIDOMWindowOuter* aWindow, nsIContent* aStartContent, int32_t aType,
    bool aNoParentTraversal, nsIContent** aNextContent) {
  *aNextContent = nullptr;

  // True if we are navigating by document (F6/Shift+F6) or false if we are
  // navigating by element (Tab/Shift+Tab).
  bool forDocumentNavigation = false;

  // This is used for document navigation only. It will be set to true if we
  // start navigating from a starting point. If this starting point is near the
  // end of the document (for example, an element on a statusbar), and there
  // are no child documents or panels before the end of the document, then we
  // will need to ensure that we don't consider the root chrome window when we
  // loop around and instead find the next child document/panel, as focus is
  // already in that window. This flag will be cleared once we navigate into
  // another document.
  bool mayFocusRoot = (aStartContent != nullptr);

  nsCOMPtr<nsIContent> startContent = aStartContent;
  if (!startContent && aType != MOVEFOCUS_CARET) {
    if (aType == MOVEFOCUS_FORWARDDOC || aType == MOVEFOCUS_BACKWARDDOC) {
      // When moving between documents, make sure to get the right
      // starting content in a descendant.
      nsCOMPtr<nsPIDOMWindowOuter> focusedWindow;
      startContent = GetFocusedDescendant(aWindow, eIncludeAllDescendants,
                                          getter_AddRefs(focusedWindow));
    } else if (aType != MOVEFOCUS_LASTDOC) {
      // Otherwise, start at the focused node. If MOVEFOCUS_LASTDOC is used,
      // then we are document-navigating backwards from chrome to the content
      // process, and we don't want to use this so that we start from the end
      // of the document.
      startContent = aWindow->GetFocusedElement();
    }
  }

  nsCOMPtr<Document> doc;
  if (startContent)
    doc = startContent->GetComposedDoc();
  else
    doc = aWindow->GetExtantDoc();
  if (!doc) return NS_OK;

  LookAndFeel::GetInt(LookAndFeel::eIntID_TabFocusModel,
                      &nsIContent::sTabFocusModel);

  // These types are for document navigation using F6.
  if (aType == MOVEFOCUS_FORWARDDOC || aType == MOVEFOCUS_BACKWARDDOC ||
      aType == MOVEFOCUS_FIRSTDOC || aType == MOVEFOCUS_LASTDOC) {
    forDocumentNavigation = true;
  }

  // If moving to the root or first document, find the root element and return.
  if (aType == MOVEFOCUS_ROOT || aType == MOVEFOCUS_FIRSTDOC) {
    NS_IF_ADDREF(*aNextContent = GetRootForFocus(aWindow, doc, false, false));
    if (!*aNextContent && aType == MOVEFOCUS_FIRSTDOC) {
      // When looking for the first document, if the root wasn't focusable,
      // find the next focusable document.
      aType = MOVEFOCUS_FORWARDDOC;
    } else {
      return NS_OK;
    }
  }

  Element* rootContent = doc->GetRootElement();
  NS_ENSURE_TRUE(rootContent, NS_OK);

  nsIPresShell* presShell = doc->GetShell();
  NS_ENSURE_TRUE(presShell, NS_OK);

  if (aType == MOVEFOCUS_FIRST) {
    if (!aStartContent) startContent = rootContent;
    return GetNextTabbableContent(presShell, startContent, nullptr,
                                  startContent, true, 1, false, false,
                                  aNextContent);
  }
  if (aType == MOVEFOCUS_LAST) {
    if (!aStartContent) startContent = rootContent;
    return GetNextTabbableContent(presShell, startContent, nullptr,
                                  startContent, false, 0, false, false,
                                  aNextContent);
  }

  bool forward = (aType == MOVEFOCUS_FORWARD || aType == MOVEFOCUS_FORWARDDOC ||
                  aType == MOVEFOCUS_CARET);
  bool doNavigation = true;
  bool ignoreTabIndex = false;
  // when a popup is open, we want to ensure that tab navigation occurs only
  // within the most recently opened panel. If a popup is open, its frame will
  // be stored in popupFrame.
  nsIFrame* popupFrame = nullptr;

  int32_t tabIndex = forward ? 1 : 0;
  if (startContent) {
    nsIFrame* frame = startContent->GetPrimaryFrame();
    if (startContent->IsHTMLElement(nsGkAtoms::area))
      startContent->IsFocusable(&tabIndex);
    else if (frame)
      frame->IsFocusable(&tabIndex, 0);
    else
      startContent->IsFocusable(&tabIndex);

    // if the current element isn't tabbable, ignore the tabindex and just
    // look for the next element. The root content won't have a tabindex
    // so just treat this as the beginning of the tab order.
    if (tabIndex < 0) {
      tabIndex = 1;
      if (startContent != rootContent) ignoreTabIndex = true;
    }

    // check if the focus is currently inside a popup. Elements such as the
    // autocomplete widget use the noautofocus attribute to allow the focus to
    // remain outside the popup when it is opened.
    if (frame) {
      popupFrame = nsLayoutUtils::GetClosestFrameOfType(
          frame, LayoutFrameType::MenuPopup);
    }

    if (popupFrame && !forDocumentNavigation) {
      // Don't navigate outside of a popup, so pretend that the
      // root content is the popup itself
      rootContent = popupFrame->GetContent()->AsElement();
      NS_ASSERTION(rootContent, "Popup frame doesn't have a content node");
    } else if (!forward) {
      // If focus moves backward and when current focused node is root
      // content or <body> element which is editable by contenteditable
      // attribute, focus should move to its parent document.
      if (startContent == rootContent) {
        doNavigation = false;
      } else {
        Document* doc = startContent->GetComposedDoc();
        if (startContent ==
            nsLayoutUtils::GetEditableRootContentByContentEditable(doc)) {
          doNavigation = false;
        }
      }
    }
  } else {
#ifdef MOZ_XUL
    if (aType != MOVEFOCUS_CARET) {
      // if there is no focus, yet a panel is open, focus the first item in
      // the panel
      nsXULPopupManager* pm = nsXULPopupManager::GetInstance();
      if (pm) popupFrame = pm->GetTopPopup(ePopupTypePanel);
    }
#endif
    if (popupFrame) {
      // When there is a popup open, and no starting content, start the search
      // at the topmost popup.
      startContent = popupFrame->GetContent();
      NS_ASSERTION(startContent, "Popup frame doesn't have a content node");
      // Unless we are searching for documents, set the root content to the
      // popup as well, so that we don't tab-navigate outside the popup.
      // When navigating by documents, we start at the popup but can navigate
      // outside of it to look for other panels and documents.
      if (!forDocumentNavigation) {
        rootContent = startContent->AsElement();
      }

      doc = startContent ? startContent->GetComposedDoc() : nullptr;
    } else {
      // Otherwise, for content shells, start from the location of the caret.
      nsCOMPtr<nsIDocShell> docShell = aWindow->GetDocShell();
      if (docShell && docShell->ItemType() != nsIDocShellTreeItem::typeChrome) {
        nsCOMPtr<nsIContent> endSelectionContent;
        GetSelectionLocation(doc, presShell, getter_AddRefs(startContent),
                             getter_AddRefs(endSelectionContent));
        // If the selection is on the rootContent, then there is no selection
        if (startContent == rootContent) {
          startContent = nullptr;
        }

        if (aType == MOVEFOCUS_CARET) {
          // GetFocusInSelection finds a focusable link near the caret.
          // If there is no start content though, don't do this to avoid
          // focusing something unexpected.
          if (startContent) {
            GetFocusInSelection(aWindow, startContent, endSelectionContent,
                                aNextContent);
          }
          return NS_OK;
        }

        if (startContent) {
          // when starting from a selection, we always want to find the next or
          // previous element in the document. So the tabindex on elements
          // should be ignored.
          ignoreTabIndex = true;
        }
      }

      if (!startContent) {
        // otherwise, just use the root content as the starting point
        startContent = rootContent;
        NS_ENSURE_TRUE(startContent, NS_OK);
      }
    }
  }

  // Check if the starting content is the same as the content assigned to the
  // retargetdocumentfocus attribute. Is so, we don't want to start searching
  // from there but instead from the beginning of the document. Otherwise, the
  // content that appears before the retargetdocumentfocus element will never
  // get checked as it will be skipped when the focus is retargetted to it.
  if (forDocumentNavigation && nsContentUtils::IsChromeDoc(doc)) {
    nsAutoString retarget;

    if (rootContent->GetAttr(kNameSpaceID_None,
                             nsGkAtoms::retargetdocumentfocus, retarget)) {
      nsIContent* retargetElement = doc->GetElementById(retarget);
      // The common case here is the urlbar where focus is on the anonymous
      // input inside the textbox, but the retargetdocumentfocus attribute
      // refers to the textbox. The Contains check will return false and the
      // ContentIsDescendantOf check will return true in this case.
      if (retargetElement && (retargetElement == startContent ||
                              (!retargetElement->Contains(startContent) &&
                               nsContentUtils::ContentIsDescendantOf(
                                   startContent, retargetElement)))) {
        startContent = rootContent;
      }
    }
  }

  NS_ASSERTION(startContent, "starting content not set");

  // keep a reference to the starting content. If we find that again, it means
  // we've iterated around completely and we don't want to adjust the focus.
  // The skipOriginalContentCheck will be set to true only for the first time
  // GetNextTabbableContent is called. This ensures that we don't break out
  // when nothing is focused to start with. Specifically,
  // GetNextTabbableContent first checks the root content -- which happens to
  // be the same as the start content -- when nothing is focused and tabbing
  // forward. Without skipOriginalContentCheck set to true, we'd end up
  // returning right away and focusing nothing. Luckily, GetNextTabbableContent
  // will never wrap around on its own, and can only return the original
  // content when it is called a second time or later.
  bool skipOriginalContentCheck = true;
  nsIContent* originalStartContent = startContent;

  LOGCONTENTNAVIGATION("Focus Navigation Start Content %s", startContent.get());
  LOGFOCUSNAVIGATION(("  Forward: %d Tabindex: %d Ignore: %d DocNav: %d",
                      forward, tabIndex, ignoreTabIndex,
                      forDocumentNavigation));

  while (doc) {
    if (doNavigation) {
      nsCOMPtr<nsIContent> nextFocus;
      nsresult rv = GetNextTabbableContent(
          presShell, rootContent,
          skipOriginalContentCheck ? nullptr : originalStartContent,
          startContent, forward, tabIndex, ignoreTabIndex,
          forDocumentNavigation, getter_AddRefs(nextFocus));
      NS_ENSURE_SUCCESS(rv, rv);
      if (rv == NS_SUCCESS_DOM_NO_OPERATION) {
        // Navigation was redirected to a child process, so just return.
        return NS_OK;
      }

      // found a content node to focus.
      if (nextFocus) {
        LOGCONTENTNAVIGATION("Next Content: %s", nextFocus.get());

        // as long as the found node was not the same as the starting node,
        // set it as the return value. For document navigation, we can return
        // the same element in case there is only one content node that could
        // be returned, for example, in a child process document.
        if (nextFocus != originalStartContent || forDocumentNavigation) {
          nextFocus.forget(aNextContent);
        }
        return NS_OK;
      }

      if (popupFrame && !forDocumentNavigation) {
        // in a popup, so start again from the beginning of the popup. However,
        // if we already started at the beginning, then there isn't anything to
        // focus, so just return
        if (startContent != rootContent) {
          startContent = rootContent;
          tabIndex = forward ? 1 : 0;
          continue;
        }
        return NS_OK;
      }
    }

    doNavigation = true;
    skipOriginalContentCheck = forDocumentNavigation;
    ignoreTabIndex = false;

    if (aNoParentTraversal) {
      if (startContent == rootContent) return NS_OK;

      startContent = rootContent;
      tabIndex = forward ? 1 : 0;
      continue;
    }

    // Reached the beginning or end of the document. Next, navigate up to the
    // parent document and try again.
    nsCOMPtr<nsPIDOMWindowOuter> piWindow = doc->GetWindow();
    NS_ENSURE_TRUE(piWindow, NS_ERROR_FAILURE);

    nsCOMPtr<nsIDocShell> docShell = piWindow->GetDocShell();
    NS_ENSURE_TRUE(docShell, NS_ERROR_FAILURE);

    // Get the frame element this window is inside and, from that, get the
    // parent document and presshell. If there is no enclosing frame element,
    // then this is a top-level, embedded or remote window.
    startContent = piWindow->GetFrameElementInternal();
    if (startContent) {
      doc = startContent->GetComposedDoc();
      NS_ENSURE_TRUE(doc, NS_ERROR_FAILURE);

      rootContent = doc->GetRootElement();
      presShell = doc->GetShell();

      // We can focus the root element now that we have moved to another
      // document.
      mayFocusRoot = true;

      nsIFrame* frame = startContent->GetPrimaryFrame();
      if (!frame) {
        return NS_OK;
      }

      frame->IsFocusable(&tabIndex, 0);
      if (tabIndex < 0) {
        tabIndex = 1;
        ignoreTabIndex = true;
      }

      // if the frame is inside a popup, make sure to scan only within the
      // popup. This handles the situation of tabbing amongst elements
      // inside an iframe which is itself inside a popup. Otherwise,
      // navigation would move outside the popup when tabbing outside the
      // iframe.
      if (!forDocumentNavigation) {
        popupFrame = nsLayoutUtils::GetClosestFrameOfType(
            frame, LayoutFrameType::MenuPopup);
        if (popupFrame) {
          rootContent = popupFrame->GetContent()->AsElement();
          NS_ASSERTION(rootContent, "Popup frame doesn't have a content node");
        }
      }
    } else {
      // There is no parent, so call the tree owner. This will tell the
      // embedder or parent process that it should take the focus.
      bool tookFocus;
      docShell->TabToTreeOwner(forward, forDocumentNavigation, &tookFocus);
      // If the tree owner took the focus, blur the current element.
      if (tookFocus) {
        nsCOMPtr<nsPIDOMWindowOuter> window = docShell->GetWindow();
        if (window->GetFocusedElement() == mFocusedElement)
          Blur(mFocusedWindow, nullptr, true, true);
        else
          window->SetFocusedElement(nullptr);
        return NS_OK;
      }

      // If we have reached the end of the top-level document, focus the
      // first element in the top-level document. This should always happen
      // when navigating by document forwards but when navigating backwards,
      // only do this if we started in another document or within a popup frame.
      // If the focus started in this window outside a popup however, we should
      // continue by looping around to the end again.
      if (forDocumentNavigation && (forward || mayFocusRoot || popupFrame)) {
        // HTML content documents can have their root element focused (a focus
        // ring appears around the entire content area frame). This root
        // appears in the tab order before all of the elements in the document.
        // Chrome documents however cannot be focused directly, so instead we
        // focus the first focusable element within the window.
        // For example, the urlbar.
        Element* root = GetRootForFocus(piWindow, doc, true, true);
        return FocusFirst(root, aNextContent);
      }

      // Once we have hit the top-level and have iterated to the end again, we
      // just want to break out next time we hit this spot to prevent infinite
      // iteration.
      mayFocusRoot = true;

      // reset the tab index and start again from the beginning or end
      startContent = rootContent;
      tabIndex = forward ? 1 : 0;
    }

    // wrapped all the way around and didn't find anything to move the focus
    // to, so just break out
    if (startContent == originalStartContent) break;
  }

  return NS_OK;
}

static bool IsHostOrSlot(const nsIContent* aContent) {
  return aContent->GetShadowRoot() || aContent->IsHTMLElement(nsGkAtoms::slot);
}

// Helper class to iterate contents in scope by traversing flattened tree
// in tree order
class MOZ_STACK_CLASS ScopedContentTraversal {
 public:
  ScopedContentTraversal(nsIContent* aStartContent, nsIContent* aOwner)
      : mCurrent(aStartContent), mOwner(aOwner) {
    MOZ_ASSERT(aStartContent);
  }

  void Next();
  void Prev();

  void Reset() { SetCurrent(mOwner); }

  nsIContent* GetCurrent() const { return mCurrent; }

 private:
  void SetCurrent(nsIContent* aContent) { mCurrent = aContent; }

  nsIContent* mCurrent;
  nsIContent* mOwner;
};

void ScopedContentTraversal::Next() {
  MOZ_ASSERT(mCurrent);

  // Get mCurrent's first child if it's in the same scope.
  if (!IsHostOrSlot(mCurrent) || mCurrent == mOwner) {
    StyleChildrenIterator iter(mCurrent);
    nsIContent* child = iter.GetNextChild();
    if (child) {
      SetCurrent(child);
      return;
    }
  }

  // If mOwner has no children, END traversal
  if (mCurrent == mOwner) {
    SetCurrent(nullptr);
    return;
  }

  nsIContent* current = mCurrent;
  while (1) {
    // Create parent's iterator and move to current
    nsIContent* parent = current->GetFlattenedTreeParent();
    StyleChildrenIterator parentIter(parent);
    parentIter.Seek(current);

    // Get next sibling of current
    if (nsIContent* next = parentIter.GetNextChild()) {
      SetCurrent(next);
      return;
    }

    // If no next sibling and parent is mOwner, END traversal
    if (parent == mOwner) {
      SetCurrent(nullptr);
      return;
    }

    current = parent;
  }
}

void ScopedContentTraversal::Prev() {
  MOZ_ASSERT(mCurrent);

  nsIContent* parent;
  nsIContent* last;
  if (mCurrent == mOwner) {
    // Get last child of mOwner
    StyleChildrenIterator ownerIter(mOwner, false /* aStartAtBeginning */);
    last = ownerIter.GetPreviousChild();

    parent = last;
  } else {
    // Create parent's iterator and move to mCurrent
    parent = mCurrent->GetFlattenedTreeParent();
    StyleChildrenIterator parentIter(parent);
    parentIter.Seek(mCurrent);

    // Get previous sibling
    last = parentIter.GetPreviousChild();
  }

  while (last) {
    parent = last;
    if (IsHostOrSlot(parent)) {
      // Skip contents in other scopes
      break;
    }

    // Find last child
    StyleChildrenIterator iter(parent, false /* aStartAtBeginning */);
    last = iter.GetPreviousChild();
  }

  // If parent is mOwner and no previous sibling remains, END traversal
  SetCurrent(parent == mOwner ? nullptr : parent);
}

/**
 * Returns scope owner of aContent.
 * A scope owner is either a document root, shadow host, or slot.
 */
static nsIContent* FindOwner(nsIContent* aContent) {
  nsIContent* currentContent = aContent;
  while (currentContent) {
    nsIContent* parent = currentContent->GetFlattenedTreeParent();
    if (!parent) {
      // Document root
      Document* doc = currentContent->GetUncomposedDoc();
      if (doc && doc->GetRootElement() == currentContent) {
        return currentContent;
      }

      break;
    }

    // Shadow host / Slot
    if (IsHostOrSlot(parent)) {
      return parent;
    }

    currentContent = parent;
  }

  return nullptr;
}

/**
 * Host and Slot elements need to be handled as if they had tabindex 0 even
 * when they don't have the attribute. This is a helper method to get the
 * right value for focus navigation. If aIsFocusable is passed, it is set to
 * true if the element itself is focusable.
 */
static int32_t HostOrSlotTabIndexValue(const nsIContent* aContent,
                                       bool* aIsFocusable = nullptr) {
  MOZ_ASSERT(IsHostOrSlot(aContent));

  if (aIsFocusable) {
    *aIsFocusable = false;
    nsIFrame* frame = aContent->GetPrimaryFrame();
    if (frame) {
      int32_t tabIndex;
      frame->IsFocusable(&tabIndex, 0);
      *aIsFocusable = tabIndex >= 0;
    }
  }

  const nsAttrValue* attrVal =
      aContent->AsElement()->GetParsedAttr(nsGkAtoms::tabindex);
  if (!attrVal) {
    return 0;
  }

  if (attrVal->Type() == nsAttrValue::eInteger) {
    return attrVal->GetIntegerValue();
  }

  return -1;
}

nsIContent* nsFocusManager::GetNextTabbableContentInScope(
    nsIContent* aOwner, nsIContent* aStartContent,
    nsIContent* aOriginalStartContent, bool aForward, int32_t aCurrentTabIndex,
    bool aIgnoreTabIndex, bool aForDocumentNavigation, bool aSkipOwner) {
  MOZ_ASSERT(IsHostOrSlot(aOwner), "Scope owner should be host or slot");

  if (!aSkipOwner && (aForward && aOwner == aStartContent)) {
    int32_t tabIndex = -1;
    nsIFrame* frame = aOwner->GetPrimaryFrame();
    if (frame && frame->IsFocusable(&tabIndex, false) && tabIndex >= 0) {
      return aOwner;
    }
  }

  //
  // Iterate contents in scope
  //
  ScopedContentTraversal contentTraversal(aStartContent, aOwner);
  nsCOMPtr<nsIContent> iterContent;
  nsIContent* firstNonChromeOnly =
      aStartContent->IsInNativeAnonymousSubtree()
          ? aStartContent->FindFirstNonChromeOnlyAccessContent()
          : nullptr;
  while (1) {
    // Iterate tab index to find corresponding contents in scope

    while (1) {
      // Iterate remaining contents in scope to find next content to focus

      // Get next content
      aForward ? contentTraversal.Next() : contentTraversal.Prev();
      iterContent = contentTraversal.GetCurrent();

      if (firstNonChromeOnly && firstNonChromeOnly == iterContent) {
        // We just broke out from the native anonymous content, so move
        // to the previous/next node of the native anonymous owner.
        if (aForward) {
          contentTraversal.Next();
        } else {
          contentTraversal.Prev();
        }
        iterContent = contentTraversal.GetCurrent();
      }
      if (!iterContent) {
        // Reach the end
        break;
      }

      int32_t tabIndex = 0;
      if (iterContent->IsInNativeAnonymousSubtree() &&
          iterContent->GetPrimaryFrame()) {
        iterContent->GetPrimaryFrame()->IsFocusable(&tabIndex);
      } else if (IsHostOrSlot(iterContent)) {
        tabIndex = HostOrSlotTabIndexValue(iterContent);
      } else {
        nsIFrame* frame = iterContent->GetPrimaryFrame();
        if (!frame) {
          continue;
        }
        frame->IsFocusable(&tabIndex, 0);
      }
      if (tabIndex < 0 || !(aIgnoreTabIndex || tabIndex == aCurrentTabIndex)) {
        continue;
      }

      if (!IsHostOrSlot(iterContent)) {
        nsCOMPtr<nsIContent> elementInFrame;
        bool checkSubDocument = true;
        if (aForDocumentNavigation &&
            TryDocumentNavigation(iterContent, &checkSubDocument,
                                  getter_AddRefs(elementInFrame))) {
          return elementInFrame;
        }
        if (!checkSubDocument) {
          continue;
        }

        if (TryToMoveFocusToSubDocument(iterContent, aOriginalStartContent,
                                        aForward, aForDocumentNavigation,
                                        getter_AddRefs(elementInFrame))) {
          return elementInFrame;
        }

        // Found content to focus
        return iterContent;
      }

      // Search in scope owned by iterContent
      nsIContent* contentToFocus = GetNextTabbableContentInScope(
          iterContent, iterContent, aOriginalStartContent, aForward,
          aForward ? 1 : 0, aIgnoreTabIndex, aForDocumentNavigation,
          false /* aSkipOwner */);
      if (contentToFocus) {
        return contentToFocus;
      }
    };

    // If already at lowest priority tab (0), end search completely.
    // A bit counterintuitive but true, tabindex order goes 1, 2, ... 32767, 0
    if (aCurrentTabIndex == (aForward ? 0 : 1)) {
      break;
    }

    // Continue looking for next highest priority tabindex
    aCurrentTabIndex = GetNextTabIndex(aOwner, aCurrentTabIndex, aForward);
    contentTraversal.Reset();
  }

  // Return scope owner at last for backward navigation if its tabindex
  // is non-negative
  if (!aSkipOwner && !aForward) {
    int32_t tabIndex = -1;
    nsIFrame* frame = aOwner->GetPrimaryFrame();
    if (frame && frame->IsFocusable(&tabIndex, false) && tabIndex >= 0) {
      return aOwner;
    }
  }

  return nullptr;
}

nsIContent* nsFocusManager::GetNextTabbableContentInAncestorScopes(
    nsIContent* aStartOwner, nsIContent** aStartContent,
    nsIContent* aOriginalStartContent, bool aForward, int32_t* aCurrentTabIndex,
    bool aIgnoreTabIndex, bool aForDocumentNavigation) {
  MOZ_ASSERT(aStartOwner == FindOwner(*aStartContent),
             "aStartOWner should be the scope owner of aStartContent");
  MOZ_ASSERT(IsHostOrSlot(aStartOwner), "scope owner should be host or slot");

  nsIContent* owner = aStartOwner;
  nsIContent* startContent = *aStartContent;
  while (IsHostOrSlot(owner)) {
    int32_t tabIndex = 0;
    if (IsHostOrSlot(startContent)) {
      tabIndex = HostOrSlotTabIndexValue(startContent);
    } else if (nsIFrame* frame = startContent->GetPrimaryFrame()) {
      frame->IsFocusable(&tabIndex);
    } else {
      startContent->IsFocusable(&tabIndex);
    }
    nsIContent* contentToFocus = GetNextTabbableContentInScope(
        owner, startContent, aOriginalStartContent, aForward, tabIndex,
        aIgnoreTabIndex, aForDocumentNavigation, false /* aSkipOwner */);
    if (contentToFocus) {
      return contentToFocus;
    }

    startContent = owner;
    owner = FindOwner(startContent);
  }

  // If not found in shadow DOM, search from the top level shadow host in light
  // DOM
  *aStartContent = startContent;
  *aCurrentTabIndex = HostOrSlotTabIndexValue(startContent);

  return nullptr;
}

static nsIContent* GetTopLevelScopeOwner(nsIContent* aContent) {
  nsIContent* topLevelScopeOwner = nullptr;
  while (aContent) {
    if (HTMLSlotElement* slot = aContent->GetAssignedSlot()) {
      aContent = slot;
    } else if (ShadowRoot* shadowRoot = aContent->GetContainingShadow()) {
      aContent = shadowRoot->Host();
      topLevelScopeOwner = aContent;
    } else {
      if (HTMLSlotElement::FromNode(aContent)) {
        topLevelScopeOwner = aContent;
      }
      aContent = aContent->GetParent();
    }
  }

  return topLevelScopeOwner;
}

nsresult nsFocusManager::GetNextTabbableContent(
    nsIPresShell* aPresShell, nsIContent* aRootContent,
    nsIContent* aOriginalStartContent, nsIContent* aStartContent, bool aForward,
    int32_t aCurrentTabIndex, bool aIgnoreTabIndex, bool aForDocumentNavigation,
    nsIContent** aResultContent) {
  *aResultContent = nullptr;

  nsCOMPtr<nsIContent> startContent = aStartContent;
  if (!startContent) return NS_OK;

  nsIContent* currentTopLevelScopeOwner = GetTopLevelScopeOwner(aStartContent);

  LOGCONTENTNAVIGATION("GetNextTabbable: %s", aStartContent);
  LOGFOCUSNAVIGATION(("  tabindex: %d", aCurrentTabIndex));

  // If aStartContent is a shadow host or slot in forward navigation,
  // search in scope owned by aStartContent
  if (aForward && IsHostOrSlot(aStartContent)) {
    nsIContent* contentToFocus = GetNextTabbableContentInScope(
        aStartContent, aStartContent, aOriginalStartContent, aForward,
        aForward ? 1 : 0, aIgnoreTabIndex, aForDocumentNavigation,
        true /* aSkipOwner */);
    if (contentToFocus) {
      NS_ADDREF(*aResultContent = contentToFocus);
      return NS_OK;
    }
  }

  // If aStartContent is not in a scope owned by the root element
  // (i.e. aStartContent is already in shadow DOM),
  // search from scope including aStartContent
  nsIContent* rootElement = aRootContent->OwnerDoc()->GetRootElement();
  nsIContent* owner = FindOwner(aStartContent);
  if (owner && rootElement != owner) {
    nsIContent* contentToFocus = GetNextTabbableContentInAncestorScopes(
        owner, &aStartContent, aOriginalStartContent, aForward,
        &aCurrentTabIndex, aIgnoreTabIndex, aForDocumentNavigation);
    if (contentToFocus) {
      NS_ADDREF(*aResultContent = contentToFocus);
      return NS_OK;
    }
  }

  // If we reach here, it means no next tabbable content in shadow DOM.
  // We need to continue searching in light DOM, starting at the top level
  // shadow host in light DOM (updated aStartContent) and its tabindex
  // (updated aCurrentTabIndex).
  MOZ_ASSERT(FindOwner(aStartContent) == rootElement,
             "aStartContent should be owned by the root element at this point");

  nsPresContext* presContext = aPresShell->GetPresContext();

  bool getNextFrame = true;
  nsCOMPtr<nsIContent> iterStartContent = aStartContent;
  // Iterate tab index to find corresponding contents
  while (1) {
    nsIFrame* frame = iterStartContent->GetPrimaryFrame();
    // if there is no frame, look for another content node that has a frame
    while (!frame) {
      // if the root content doesn't have a frame, just return
      if (iterStartContent == aRootContent) {
        return NS_OK;
      }

      // look for the next or previous content node in tree order
      iterStartContent = aForward ? iterStartContent->GetNextNode()
                                  : iterStartContent->GetPreviousContent();
      if (!iterStartContent) {
        break;
      }

      frame = iterStartContent->GetPrimaryFrame();
      // Host without frame, enter its scope.
      if (!frame && iterStartContent->GetShadowRoot()) {
        int32_t tabIndex = HostOrSlotTabIndexValue(iterStartContent);
        if (tabIndex >= 0 &&
            (aIgnoreTabIndex || aCurrentTabIndex == tabIndex)) {
          nsIContent* contentToFocus = GetNextTabbableContentInScope(
              iterStartContent, iterStartContent, aOriginalStartContent,
              aForward, aForward ? 1 : 0, aIgnoreTabIndex,
              aForDocumentNavigation, true /* aSkipOwner */);
          if (contentToFocus) {
            NS_ADDREF(*aResultContent = contentToFocus);
            return NS_OK;
          }
        }
      }
      // we've already skipped over the initial focused content, so we
      // don't want to traverse frames.
      getNextFrame = false;
    }

    nsCOMPtr<nsIFrameEnumerator> frameTraversal;
    if (frame) {
      // For tab navigation, pass false for aSkipPopupChecks so that we don't
      // iterate into or out of a popup. For document naviation pass true to
      // ignore these boundaries.
      nsresult rv = NS_NewFrameTraversal(
          getter_AddRefs(frameTraversal), presContext, frame, ePreOrder,
          false,                  // aVisual
          false,                  // aLockInScrollView
          true,                   // aFollowOOFs
          aForDocumentNavigation  // aSkipPopupChecks
      );
      NS_ENSURE_SUCCESS(rv, rv);

      if (iterStartContent == aRootContent) {
        if (!aForward) {
          frameTraversal->Last();
        } else if (aRootContent->IsFocusable()) {
          frameTraversal->Next();
        }
        frame = static_cast<nsIFrame*>(frameTraversal->CurrentItem());
      } else if (getNextFrame &&
                 (!iterStartContent ||
                  !iterStartContent->IsHTMLElement(nsGkAtoms::area))) {
        // Need to do special check in case we're in an imagemap which has
        // multiple content nodes per frame, so don't skip over the starting
        // frame.
        if (aForward) {
          frameTraversal->Next();
        } else {
          frameTraversal->Prev();
        }

        frame = static_cast<nsIFrame*>(frameTraversal->CurrentItem());
      }
    }

    // Walk frames to find something tabbable matching aCurrentTabIndex
    while (frame) {
      // Try to find the topmost scope owner, since we want to skip the node
      // that is not owned by document in frame traversal.
      nsIContent* currentContent = frame->GetContent();
      nsIContent* oldTopLevelScopeOwner = currentTopLevelScopeOwner;
      if (oldTopLevelScopeOwner != currentContent) {
        currentTopLevelScopeOwner = GetTopLevelScopeOwner(currentContent);
      } else {
        currentTopLevelScopeOwner = currentContent;
      }
      if (currentTopLevelScopeOwner) {
        if (currentTopLevelScopeOwner == oldTopLevelScopeOwner) {
          // We're within non-document scope, continue.
          do {
            if (aForward) {
              frameTraversal->Next();
            } else {
              frameTraversal->Prev();
            }
            frame = static_cast<nsIFrame*>(frameTraversal->CurrentItem());
            // For the usage of GetPrevContinuation, see the comment
            // at the end of while (frame) loop.
          } while (frame && frame->GetPrevContinuation());
          continue;
        }
        currentContent = currentTopLevelScopeOwner;
      }

      // For document navigation, check if this element is an open panel. Since
      // panels aren't focusable (tabIndex would be -1), we'll just assume that
      // for document navigation, the tabIndex is 0.
      if (aForDocumentNavigation && currentContent && (aCurrentTabIndex == 0) &&
          currentContent->IsXULElement(nsGkAtoms::panel)) {
        nsMenuPopupFrame* popupFrame = do_QueryFrame(frame);
        // Check if the panel is open. Closed panels are ignored since you can't
        // focus anything in them.
        if (popupFrame && popupFrame->IsOpen()) {
          // When moving backward, skip the popup we started in otherwise it
          // will be selected again.
          bool validPopup = true;
          if (!aForward) {
            nsIContent* content = aStartContent;
            while (content) {
              if (content == currentContent) {
                validPopup = false;
                break;
              }

              content = content->GetParent();
            }
          }

          if (validPopup) {
            // Since a panel isn't focusable itself, find the first focusable
            // content within the popup. If there isn't any focusable content
            // in the popup, skip this popup and continue iterating through the
            // frames. We pass the panel itself (currentContent) as the starting
            // and root content, so that we only find content within the panel.
            // Note also that we pass false for aForDocumentNavigation since we
            // want to locate the first content, not the first document.
            nsresult rv = GetNextTabbableContent(
                aPresShell, currentContent, nullptr, currentContent, true, 1,
                false, false, aResultContent);
            if (NS_SUCCEEDED(rv) && *aResultContent) {
              return rv;
            }
          }
        }
      }

      // As of now, 2018/04/12, sequential focus navigation is still
      // in the obsolete Shadow DOM specification.
      // http://w3c.github.io/webcomponents/spec/shadow/#sequential-focus-navigation
      // "if ELEMENT is focusable, a shadow host, or a slot element,
      //  append ELEMENT to NAVIGATION-ORDER."
      // and later in "For each element ELEMENT in NAVIGATION-ORDER: "
      // hosts and slots are handled before other elements.
      if (currentContent && IsHostOrSlot(currentContent)) {
        bool focusableHostSlot;
        int32_t tabIndex =
            HostOrSlotTabIndexValue(currentContent, &focusableHostSlot);
        // Host or slot itself isn't focusable or going backwards, enter its
        // scope.
        if ((!aForward || !focusableHostSlot) && tabIndex >= 0 &&
            (aIgnoreTabIndex || aCurrentTabIndex == tabIndex)) {
          nsIContent* contentToFocus = GetNextTabbableContentInScope(
              currentContent, currentContent, aOriginalStartContent, aForward,
              aForward ? 1 : 0, aIgnoreTabIndex, aForDocumentNavigation,
              true /* aSkipOwner */);
          if (contentToFocus) {
            NS_ADDREF(*aResultContent = contentToFocus);
            return NS_OK;
          }
        }
      }

      // TabIndex not set defaults to 0 for form elements, anchors and other
      // elements that are normally focusable. Tabindex defaults to -1
      // for elements that are not normally focusable.
      // The returned computed tabindex from IsFocusable() is as follows:
      // clang-format off
      //          < 0 not tabbable at all
      //          == 0 in normal tab order (last after positive tabindexed items)
      //          > 0 can be tabbed to in the order specified by this value
      // clang-format on
      int32_t tabIndex;
      frame->IsFocusable(&tabIndex, 0);

      LOGCONTENTNAVIGATION("Next Tabbable %s:", frame->GetContent());
      LOGFOCUSNAVIGATION(
          ("  with tabindex: %d expected: %d", tabIndex, aCurrentTabIndex));

      if (tabIndex >= 0) {
        NS_ASSERTION(currentContent,
                     "IsFocusable set a tabindex for a frame with no content");
        if (!aForDocumentNavigation &&
            currentContent->IsHTMLElement(nsGkAtoms::img) &&
            currentContent->AsElement()->HasAttr(kNameSpaceID_None,
                                                 nsGkAtoms::usemap)) {
          // This is an image with a map. Image map areas are not traversed by
          // nsIFrameTraversal so look for the next or previous area element.
          nsIContent* areaContent = GetNextTabbableMapArea(
              aForward, aCurrentTabIndex, currentContent->AsElement(),
              iterStartContent);
          if (areaContent) {
            NS_ADDREF(*aResultContent = areaContent);
            return NS_OK;
          }
        } else if (aIgnoreTabIndex || aCurrentTabIndex == tabIndex) {
          // break out if we've wrapped around to the start again.
          if (aOriginalStartContent &&
              currentContent == aOriginalStartContent) {
            NS_ADDREF(*aResultContent = currentContent);
            return NS_OK;
          }

          // If this is a remote child browser, call NavigateDocument to have
          // the child process continue the navigation. Return a special error
          // code to have the caller return early. If the child ends up not
          // being focusable in some way, the child process will call back
          // into document navigation again by calling MoveFocus.
          TabParent* remote = TabParent::GetFrom(currentContent);
          if (remote) {
            remote->NavigateByKey(aForward, aForDocumentNavigation);
            return NS_SUCCESS_DOM_NO_OPERATION;
          }

          // Next, for document navigation, check if this a non-remote child
          // document.
          bool checkSubDocument = true;
          if (aForDocumentNavigation &&
              TryDocumentNavigation(currentContent, &checkSubDocument,
                                    aResultContent)) {
            return NS_OK;
          }

          if (checkSubDocument) {
            // found a node with a matching tab index. Check if it is a child
            // frame. If so, navigate into the child frame instead.
            if (TryToMoveFocusToSubDocument(
                    currentContent, aOriginalStartContent, aForward,
                    aForDocumentNavigation, aResultContent)) {
              MOZ_ASSERT(*aResultContent);
              return NS_OK;
            }
            // otherwise, use this as the next content node to tab to, unless
            // this was the element we started on. This would happen for
            // instance on an element with child frames, where frame navigation
            // could return the original element again. In that case, just skip
            // it. Also, if the next content node is the root content, then
            // return it. This latter case would happen only if someone made a
            // popup focusable.
            // Also, when going backwards, check to ensure that the focus
            // wouldn't be redirected. Otherwise, for example, when an input in
            // a textbox is focused, the enclosing textbox would be found and
            // the same inner input would be returned again.
            else if (currentContent == aRootContent ||
                     (currentContent != startContent &&
                      (aForward || !GetRedirectedFocus(currentContent)))) {
              NS_ADDREF(*aResultContent = currentContent);
              return NS_OK;
            }
          }
        }
      } else if (aOriginalStartContent &&
                 currentContent == aOriginalStartContent) {
        // not focusable, so return if we have wrapped around to the original
        // content. This is necessary in case the original starting content was
        // not focusable.
        NS_ADDREF(*aResultContent = currentContent);
        return NS_OK;
      }

      // Move to the next or previous frame, but ignore continuation frames
      // since only the first frame should be involved in focusability.
      // Otherwise, a loop will occur in the following example:
      //   <span tabindex="1">...<a/><a/>...</span>
      // where the text wraps onto multiple lines. Tabbing from the second
      // link can find one of the span's continuation frames between the link
      // and the end of the span, and the span would end up getting focused
      // again.
      do {
        if (aForward)
          frameTraversal->Next();
        else
          frameTraversal->Prev();
        frame = static_cast<nsIFrame*>(frameTraversal->CurrentItem());
      } while (frame && frame->GetPrevContinuation());
    }

    // If already at lowest priority tab (0), end search completely.
    // A bit counterintuitive but true, tabindex order goes 1, 2, ... 32767, 0
    if (aCurrentTabIndex == (aForward ? 0 : 1)) {
      // if going backwards, the canvas should be focused once the beginning
      // has been reached, so get the root element.
      if (!aForward) {
        nsCOMPtr<nsPIDOMWindowOuter> window = GetCurrentWindow(aRootContent);
        NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);

        RefPtr<Element> docRoot = GetRootForFocus(
            window, aRootContent->GetComposedDoc(), false, true);
        FocusFirst(docRoot, aResultContent);
      }
      break;
    }

    // continue looking for next highest priority tabindex
    aCurrentTabIndex =
        GetNextTabIndex(aRootContent, aCurrentTabIndex, aForward);
    startContent = iterStartContent = aRootContent;
  }

  return NS_OK;
}

bool nsFocusManager::TryDocumentNavigation(nsIContent* aCurrentContent,
                                           bool* aCheckSubDocument,
                                           nsIContent** aResultContent) {
  *aCheckSubDocument = true;
  Element* docRoot = GetRootForChildDocument(aCurrentContent);
  if (docRoot) {
    // If GetRootForChildDocument returned something then call
    // FocusFirst to find the root or first element to focus within
    // the child document. If this is a frameset though, skip this and
    // fall through to normal tab navigation to iterate into
    // the frameset's frames and locate the first focusable frame.
    if (!docRoot->IsHTMLElement(nsGkAtoms::frameset)) {
      *aCheckSubDocument = false;
      Unused << FocusFirst(docRoot, aResultContent);
      return *aResultContent != nullptr;
    }
  } else {
    // Set aCheckSubDocument to false, as this was neither a frame
    // type element or a child document that was focusable.
    *aCheckSubDocument = false;
  }

  return false;
}

bool nsFocusManager::TryToMoveFocusToSubDocument(
    nsIContent* aCurrentContent, nsIContent* aOriginalStartContent,
    bool aForward, bool aForDocumentNavigation, nsIContent** aResultContent) {
  Document* doc = aCurrentContent->GetComposedDoc();
  NS_ASSERTION(doc, "content not in document");
  Document* subdoc = doc->GetSubDocumentFor(aCurrentContent);
  if (subdoc && !subdoc->EventHandlingSuppressed()) {
    if (aForward) {
      // When tabbing forward into a frame, return the root
      // frame so that the canvas becomes focused.
      nsCOMPtr<nsPIDOMWindowOuter> subframe = subdoc->GetWindow();
      if (subframe) {
        *aResultContent = GetRootForFocus(subframe, subdoc, false, true);
        if (*aResultContent) {
          NS_ADDREF(*aResultContent);
          return true;
        }
      }
    }
    Element* rootElement = subdoc->GetRootElement();
    nsIPresShell* subShell = subdoc->GetShell();
    if (rootElement && subShell) {
      nsresult rv = GetNextTabbableContent(
          subShell, rootElement, aOriginalStartContent, rootElement, aForward,
          (aForward ? 1 : 0), false, aForDocumentNavigation, aResultContent);
      NS_ENSURE_SUCCESS(rv, false);
      if (*aResultContent) {
        return true;
      }
    }
  }
  return false;
}

nsIContent* nsFocusManager::GetNextTabbableMapArea(bool aForward,
                                                   int32_t aCurrentTabIndex,
                                                   Element* aImageContent,
                                                   nsIContent* aStartContent) {
  if (aImageContent->IsInComposedDoc()) {
    HTMLImageElement* imgElement = HTMLImageElement::FromNode(aImageContent);
    // The caller should check the element type, so we can assert here.
    MOZ_ASSERT(imgElement);

    nsCOMPtr<nsIContent> mapContent = imgElement->FindImageMap();
    if (!mapContent) return nullptr;
    uint32_t count = mapContent->GetChildCount();
    // First see if the the start content is in this map

    int32_t index = mapContent->ComputeIndexOf(aStartContent);
    int32_t tabIndex;
    if (index < 0 || (aStartContent->IsFocusable(&tabIndex) &&
                      tabIndex != aCurrentTabIndex)) {
      // If aStartContent is in this map we must start iterating past it.
      // We skip the case where aStartContent has tabindex == aStartContent
      // since the next tab ordered element might be before it
      // (or after for backwards) in the child list.
      index = aForward ? -1 : (int32_t)count;
    }

    // GetChildAt_Deprecated will return nullptr if our index < 0 or index >=
    // count
    nsCOMPtr<nsIContent> areaContent;
    while ((areaContent = mapContent->GetChildAt_Deprecated(
                aForward ? ++index : --index)) != nullptr) {
      if (areaContent->IsFocusable(&tabIndex) && tabIndex == aCurrentTabIndex) {
        return areaContent;
      }
    }
  }

  return nullptr;
}

int32_t nsFocusManager::GetNextTabIndex(nsIContent* aParent,
                                        int32_t aCurrentTabIndex,
                                        bool aForward) {
  int32_t tabIndex, childTabIndex;
  StyleChildrenIterator iter(aParent);

  if (aForward) {
    tabIndex = 0;
    for (nsIContent* child = iter.GetNextChild(); child;
         child = iter.GetNextChild()) {
      // Skip child's descendants if child is a shadow host or slot, as they are
      // in the focus navigation scope owned by child's shadow root
      if (!IsHostOrSlot(child)) {
        childTabIndex = GetNextTabIndex(child, aCurrentTabIndex, aForward);
        if (childTabIndex > aCurrentTabIndex && childTabIndex != tabIndex) {
          tabIndex = (tabIndex == 0 || childTabIndex < tabIndex) ? childTabIndex
                                                                 : tabIndex;
        }
      }

      nsAutoString tabIndexStr;
      if (child->IsElement()) {
        child->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::tabindex,
                                    tabIndexStr);
      }
      nsresult ec;
      int32_t val = tabIndexStr.ToInteger(&ec);
      if (NS_SUCCEEDED(ec) && val > aCurrentTabIndex && val != tabIndex) {
        tabIndex = (tabIndex == 0 || val < tabIndex) ? val : tabIndex;
      }
    }
  } else { /* !aForward */
    tabIndex = 1;
    for (nsIContent* child = iter.GetNextChild(); child;
         child = iter.GetNextChild()) {
      // Skip child's descendants if child is a shadow host or slot, as they are
      // in the focus navigation scope owned by child's shadow root
      if (!IsHostOrSlot(child)) {
        childTabIndex = GetNextTabIndex(child, aCurrentTabIndex, aForward);
        if ((aCurrentTabIndex == 0 && childTabIndex > tabIndex) ||
            (childTabIndex < aCurrentTabIndex && childTabIndex > tabIndex)) {
          tabIndex = childTabIndex;
        }
      }

      nsAutoString tabIndexStr;
      if (child->IsElement()) {
        child->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::tabindex,
                                    tabIndexStr);
      }
      nsresult ec;
      int32_t val = tabIndexStr.ToInteger(&ec);
      if (NS_SUCCEEDED(ec)) {
        if ((aCurrentTabIndex == 0 && val > tabIndex) ||
            (val < aCurrentTabIndex && val > tabIndex)) {
          tabIndex = val;
        }
      }
    }
  }

  return tabIndex;
}

nsresult nsFocusManager::FocusFirst(Element* aRootElement,
                                    nsIContent** aNextContent) {
  if (!aRootElement) {
    return NS_OK;
  }

  Document* doc = aRootElement->GetComposedDoc();
  if (doc) {
    if (nsContentUtils::IsChromeDoc(doc)) {
      // If the redirectdocumentfocus attribute is set, redirect the focus to a
      // specific element. This is primarily used to retarget the focus to the
      // urlbar during document navigation.
      nsAutoString retarget;

      if (aRootElement->GetAttr(kNameSpaceID_None,
                                nsGkAtoms::retargetdocumentfocus, retarget)) {
        nsCOMPtr<Element> element = doc->GetElementById(retarget);
        nsCOMPtr<nsIContent> retargetElement = CheckIfFocusable(element, 0);
        if (retargetElement) {
          retargetElement.forget(aNextContent);
          return NS_OK;
        }
      }
    }

    nsCOMPtr<nsIDocShell> docShell = doc->GetDocShell();
    if (docShell->ItemType() == nsIDocShellTreeItem::typeChrome) {
      // If the found content is in a chrome shell, navigate forward one
      // tabbable item so that the first item is focused. Note that we
      // always go forward and not back here.
      nsIPresShell* presShell = doc->GetShell();
      if (presShell) {
        return GetNextTabbableContent(presShell, aRootElement, nullptr,
                                      aRootElement, true, 1, false, false,
                                      aNextContent);
      }
    }
  }

  NS_ADDREF(*aNextContent = aRootElement);
  return NS_OK;
}

Element* nsFocusManager::GetRootForFocus(nsPIDOMWindowOuter* aWindow,
                                         Document* aDocument,
                                         bool aForDocumentNavigation,
                                         bool aCheckVisibility) {
  if (!aForDocumentNavigation) {
    nsCOMPtr<nsIDocShell> docShell = aWindow->GetDocShell();
    if (docShell->ItemType() == nsIDocShellTreeItem::typeChrome) {
      return nullptr;
    }
  }

  if (aCheckVisibility && !IsWindowVisible(aWindow)) return nullptr;

  // If the body is contenteditable, use the editor's root element rather than
  // the actual root element.
  RefPtr<Element> rootElement =
      nsLayoutUtils::GetEditableRootContentByContentEditable(aDocument);
  if (!rootElement || !rootElement->GetPrimaryFrame()) {
    rootElement = aDocument->GetRootElement();
    if (!rootElement) {
      return nullptr;
    }
  }

  if (aCheckVisibility && !rootElement->GetPrimaryFrame()) {
    return nullptr;
  }

  // Finally, check if this is a frameset
  nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(aDocument);
  if (htmlDoc) {
    Element* htmlChild = aDocument->GetHtmlChildElement(nsGkAtoms::frameset);
    if (htmlChild) {
      // In document navigation mode, return the frameset so that navigation
      // descends into the child frames.
      return aForDocumentNavigation ? htmlChild : nullptr;
    }
  }

  return rootElement;
}

Element* nsFocusManager::GetRootForChildDocument(nsIContent* aContent) {
  // Check for elements that represent child documents, that is, browsers,
  // editors or frames from a frameset. We don't include iframes since we
  // consider them to be an integral part of the same window or page.
  if (!aContent || !(aContent->IsXULElement(nsGkAtoms::browser) ||
                     aContent->IsXULElement(nsGkAtoms::editor) ||
                     aContent->IsHTMLElement(nsGkAtoms::frame))) {
    return nullptr;
  }

  Document* doc = aContent->GetComposedDoc();
  if (!doc) {
    return nullptr;
  }

  Document* subdoc = doc->GetSubDocumentFor(aContent);
  if (!subdoc || subdoc->EventHandlingSuppressed()) {
    return nullptr;
  }

  nsCOMPtr<nsPIDOMWindowOuter> window = subdoc->GetWindow();
  return GetRootForFocus(window, subdoc, true, true);
}

void nsFocusManager::GetFocusInSelection(nsPIDOMWindowOuter* aWindow,
                                         nsIContent* aStartSelection,
                                         nsIContent* aEndSelection,
                                         nsIContent** aFocusedContent) {
  *aFocusedContent = nullptr;

  nsCOMPtr<nsIContent> testContent = aStartSelection;
  nsCOMPtr<nsIContent> nextTestContent = aEndSelection;

  nsCOMPtr<nsIContent> currentFocus = aWindow->GetFocusedElement();

  // We now have the correct start node in selectionContent!
  // Search for focusable elements, starting with selectionContent

  // Method #1: Keep going up while we look - an ancestor might be focusable
  // We could end the loop earlier, such as when we're no longer
  // in the same frame, by comparing selectionContent->GetPrimaryFrame()
  // with a variable holding the starting selectionContent
  while (testContent) {
    // Keep testing while selectionContent is equal to something,
    // eventually we'll run out of ancestors

    nsCOMPtr<nsIURI> uri;
    if (testContent == currentFocus ||
        testContent->IsLink(getter_AddRefs(uri))) {
      testContent.forget(aFocusedContent);
      return;
    }

    // Get the parent
    testContent = testContent->GetParent();

    if (!testContent) {
      // We run this loop again, checking the ancestor chain of the selection's
      // end point
      testContent = nextTestContent;
      nextTestContent = nullptr;
    }
  }

  // We couldn't find an anchor that was an ancestor of the selection start
  // Method #2: look for anchor in selection's primary range (depth first
  // search)

  nsCOMPtr<nsIContent> selectionNode = aStartSelection;
  nsCOMPtr<nsIContent> endSelectionNode = aEndSelection;
  nsCOMPtr<nsIContent> testNode;

  do {
    testContent = selectionNode;

    // We're looking for any focusable link that could be part of the
    // main document's selection.
    nsCOMPtr<nsIURI> uri;
    if (testContent == currentFocus ||
        testContent->IsLink(getter_AddRefs(uri))) {
      testContent.forget(aFocusedContent);
      return;
    }

    nsIContent* testNode = selectionNode->GetFirstChild();
    if (testNode) {
      selectionNode = testNode;
      continue;
    }

    if (selectionNode == endSelectionNode) break;
    testNode = selectionNode->GetNextSibling();
    if (testNode) {
      selectionNode = testNode;
      continue;
    }

    do {
      // GetParent is OK here, instead of GetParentNode, because the only case
      // where the latter returns something different from the former is when
      // GetParentNode is the document.  But in that case we would simply get
      // null for selectionNode when setting it to testNode->GetNextSibling()
      // (because a document has no next sibling).  And then the next iteration
      // of this loop would get null for GetParentNode anyway, and break out of
      // all the loops.
      testNode = selectionNode->GetParent();
      if (!testNode || testNode == endSelectionNode) {
        selectionNode = nullptr;
        break;
      }
      selectionNode = testNode->GetNextSibling();
      if (selectionNode) break;
      selectionNode = testNode;
    } while (true);
  } while (selectionNode && selectionNode != endSelectionNode);
}

class PointerUnlocker : public Runnable {
 public:
  PointerUnlocker() : mozilla::Runnable("PointerUnlocker") {
    MOZ_ASSERT(!PointerUnlocker::sActiveUnlocker);
    PointerUnlocker::sActiveUnlocker = this;
  }

  ~PointerUnlocker() {
    if (PointerUnlocker::sActiveUnlocker == this) {
      PointerUnlocker::sActiveUnlocker = nullptr;
    }
  }

  NS_IMETHOD Run() override {
    if (PointerUnlocker::sActiveUnlocker == this) {
      PointerUnlocker::sActiveUnlocker = nullptr;
    }
    NS_ENSURE_STATE(nsFocusManager::GetFocusManager());
    nsPIDOMWindowOuter* focused =
        nsFocusManager::GetFocusManager()->GetFocusedWindow();
    nsCOMPtr<Document> pointerLockedDoc =
        do_QueryReferent(EventStateManager::sPointerLockedDoc);
    if (pointerLockedDoc && !nsContentUtils::IsInPointerLockContext(focused)) {
      Document::UnlockPointer();
    }
    return NS_OK;
  }

  static PointerUnlocker* sActiveUnlocker;
};

PointerUnlocker* PointerUnlocker::sActiveUnlocker = nullptr;

void nsFocusManager::SetFocusedWindowInternal(nsPIDOMWindowOuter* aWindow) {
  if (!PointerUnlocker::sActiveUnlocker &&
      nsContentUtils::IsInPointerLockContext(mFocusedWindow) &&
      !nsContentUtils::IsInPointerLockContext(aWindow)) {
    nsCOMPtr<nsIRunnable> runnable = new PointerUnlocker();
    NS_DispatchToCurrentThread(runnable);
  }

  // Update the last focus time on any affected documents
  if (aWindow && aWindow != mFocusedWindow) {
    const TimeStamp now(TimeStamp::Now());
    for (Document* doc = aWindow->GetExtantDoc(); doc;
         doc = doc->GetParentDocument()) {
      doc->SetLastFocusTime(now);
    }
  }

  mFocusedWindow = aWindow;
}

void nsFocusManager::MarkUncollectableForCCGeneration(uint32_t aGeneration) {
  if (!sInstance) {
    return;
  }

  if (sInstance->mActiveWindow) {
    sInstance->mActiveWindow->MarkUncollectableForCCGeneration(aGeneration);
  }
  if (sInstance->mFocusedWindow) {
    sInstance->mFocusedWindow->MarkUncollectableForCCGeneration(aGeneration);
  }
  if (sInstance->mWindowBeingLowered) {
    sInstance->mWindowBeingLowered->MarkUncollectableForCCGeneration(
        aGeneration);
  }
  if (sInstance->mFocusedElement) {
    sInstance->mFocusedElement->OwnerDoc()->MarkUncollectableForCCGeneration(
        aGeneration);
  }
  if (sInstance->mFirstBlurEvent) {
    sInstance->mFirstBlurEvent->OwnerDoc()->MarkUncollectableForCCGeneration(
        aGeneration);
  }
  if (sInstance->mFirstFocusEvent) {
    sInstance->mFirstFocusEvent->OwnerDoc()->MarkUncollectableForCCGeneration(
        aGeneration);
  }
  if (sInstance->mMouseButtonEventHandlingDocument) {
    sInstance->mMouseButtonEventHandlingDocument
        ->MarkUncollectableForCCGeneration(aGeneration);
  }
}

bool nsFocusManager::CanSkipFocus(nsIContent* aContent) {
  if (!aContent || nsContentUtils::IsChromeDoc(aContent->OwnerDoc())) {
    return false;
  }

  if (mFocusedElement == aContent) {
    return true;
  }

  nsIDocShell* ds = aContent->OwnerDoc()->GetDocShell();
  if (!ds) {
    return true;
  }

  nsCOMPtr<nsIDocShellTreeItem> root;
  ds->GetRootTreeItem(getter_AddRefs(root));
  nsCOMPtr<nsPIDOMWindowOuter> newRootWindow =
      root ? root->GetWindow() : nullptr;
  if (mActiveWindow != newRootWindow) {
    nsPIDOMWindowOuter* outerWindow = aContent->OwnerDoc()->GetWindow();
    if (outerWindow && outerWindow->GetFocusedElement() == aContent) {
      return true;
    }
  }

  return false;
}

nsresult NS_NewFocusManager(nsIFocusManager** aResult) {
  NS_IF_ADDREF(*aResult = nsFocusManager::GetFocusManager());
  return NS_OK;
}