Bug 1675764 [Wayland] Use explicit PipeWire entry at screen sharing dialog when PipeWire is used, r=dminor,jib,johannh

When we share content by PipeWire, a system portal is used to select which content is shared.
In that case put only PipeWire portal name placeholder to device list.

Differential Revision: https://phabricator.services.mozilla.com/D96694

browser/actors/WebRTCParent.jsm

@@ -45,6 +45,14 @@ XPCOMUtils.defineLazyServiceGetter(
   "nsIOSPermissionRequest"
 );
 
+// Keep in sync with defines at base_capturer_pipewire.cc
+// With PipeWire we can't select which system resource is shared so
+// we don't create a window/screen list. Instead we place these constants
+// as window name/id so frontend code can identify PipeWire backend
+// and does not try to create screen/window preview.
+const PIPEWIRE_PORTAL_NAME = "####_PIPEWIRE_PORTAL_####";
+const PIPEWIRE_ID = 0xaffffff;
+
 class WebRTCParent extends JSWindowActorParent {
   didDestroy() {
     webrtcUI.forgetStreamsFromBrowserContext(this.browsingContext);
@@ -774,6 +782,23 @@ function prompt(aActor, aBrowser, aRequest) {
             }
           } else {
             name = device.name;
+            // When we share content by PipeWire add only one item to the device
+            // list. When it's selected PipeWire portal dialog is opened and
+            // user confirms actual window/screen sharing there.
+            // Don't mark it as scary as there's an extra confirmation step by
+            // PipeWire portal dialog.
+            if (name == PIPEWIRE_PORTAL_NAME && device.id == PIPEWIRE_ID) {
+              let sawcStringId = "getUserMedia.sharePipeWirePortal.label";
+              let item = addDeviceToList(
+                menupopup,
+                stringBundle.getString(sawcStringId),
+                i,
+                type
+              );
+              item.deviceId = device.id;
+              item.mediaSource = type;
+              break;
+            }
             if (type == "application") {
               // The application names returned by the platform are of the form:
               // <window count>\x1e<application name>

browser/locales/en-US/chrome/browser/browser.properties

@@ -767,6 +767,7 @@ getUserMedia.selectWindowOrScreen.label=Window or Screen to share:
 getUserMedia.selectWindowOrScreen.accesskey=W
 getUserMedia.pickWindowOrScreen.label = Select Window or Screen
 getUserMedia.shareEntireScreen.label = Entire screen
+getUserMedia.sharePipeWirePortal.label = Use operating system settings
 # LOCALIZATION NOTE (getUserMedia.shareMonitor.label):
 # %S is screen number (digits 1, 2, etc)
 # Example: Screen 1, Screen 2,..

third_party/libwebrtc/webrtc/modules/desktop_capture/linux/base_capturer_pipewire.cc

@@ -898,17 +898,23 @@ void BaseCapturerPipeWire::CaptureFrame() {
   callback_->OnCaptureResult(Result::SUCCESS, std::move(result));
 }
 
+// Keep in sync with defines at browser/actors/WebRTCParent.jsm
+// With PipeWire we can't select which system resource is shared so
+// we don't create a window/screen list. Instead we place these constants
+// as window name/id so frontend code can identify PipeWire backend
+// and does not try to create screen/window preview.
+
+#define PIPEWIRE_ID   0xaffffff
+#define PIPEWIRE_NAME "####_PIPEWIRE_PORTAL_####"
+
 bool BaseCapturerPipeWire::GetSourceList(SourceList* sources) {
-  RTC_DCHECK(sources->size() == 0);
+  sources->push_back({PIPEWIRE_ID, 0, PIPEWIRE_NAME});
-  // List of available screens is already presented by the xdg-desktop-portal.
-  // But we have to add an empty source as the code expects it.
-  sources->push_back({0});
   return true;
 }
 
 bool BaseCapturerPipeWire::SelectSource(SourceId id) {
   // Screen selection is handled by the xdg-desktop-portal.
-  return true;
+  return id == PIPEWIRE_ID;
 }
 
 // static