Bug 1758997 - Remove RoInitialize/RoUninitialize from OSPreferences_win. r=Jamie

As per bug 1757647 comment 4, the main thread already initializes COM
early, and we should be able to rely on it in OSPreferences.

Differential Revision: https://phabricator.services.mozilla.com/D140745

intl/locale/windows/OSPreferences_win.cpp

@@ -35,13 +35,6 @@ bool OSPreferences::ReadSystemLocales(nsTArray<nsCString>& aLocaleList) {
     // Try to get language list from GlobalizationPreferences; if this fails,
     // we'll fall back to GetUserPreferredUILanguages.
     // Per MSDN, these APIs are not available prior to Win8.
-
-    // RoInitialize may fail with "cannot change thread mode after it is set",
-    // if the runtime was already initialized on this thread.
-    // This appears to be harmless, and we can proceed to attempt the following
-    // runtime calls.
-    HRESULT inited = RoInitialize(RO_INIT_MULTITHREADED);
-    if (SUCCEEDED(inited) || inited == RPC_E_CHANGED_MODE) {
     ComPtr<IGlobalizationPreferencesStatics> globalizationPrefs;
     ComPtr<IVectorView<HSTRING>> languages;
     uint32_t count;
@@ -80,12 +73,6 @@ bool OSPreferences::ReadSystemLocales(nsTArray<nsCString>& aLocaleList) {
       }
     }
   }
-    // Only close the runtime if we successfully initialized it above,
-    // otherwise we assume it was already in use and should be left as is.
-    if (SUCCEEDED(inited)) {
-      RoUninitialize();
-    }
-  }
 #endif
 
   // Per MSDN, GetUserPreferredUILanguages is available from Vista onwards,

tools/lint/mscom-init.yml

@@ -30,7 +30,6 @@ forbid-mscom-init:
         - browser/components/shell/nsWindowsShellService.cpp
         - gfx/thebes/gfxWindowsPlatform.cpp
         - image/DecodePool.cpp
-        - intl/locale/windows/OSPreferences_win.cpp
         - ipc/glue/BrowserProcessSubThread.cpp
         - netwerk/system/win32/nsNotifyAddrListener.cpp
         - toolkit/components/parentalcontrols/nsParentalControlsServiceWin.cpp