Bug 1189622 part 2 - Allow widget's MakeFullScreen to fail, and call FinishFullscreenChange directly if that happens. r=smaug

--HG--
extra : source : a851e10d72b71dbd7bab21e3e6ef80214f680b9b

dom/base/nsGlobalWindow.cpp

@@ -5914,8 +5914,12 @@ FullscreenTransitionTask::Run()
       mWindow->mFullScreen = mFullscreen;
     }
     // Toggle the fullscreen state on the widget
-    mWindow->SetWidgetFullscreen(nsPIDOMWindow::eForFullscreenAPI,
-                                 mFullscreen, mWidget, mScreen);
+    if (!mWindow->SetWidgetFullscreen(nsPIDOMWindow::eForFullscreenAPI,
+                                      mFullscreen, mWidget, mScreen)) {
+      // Fail to setup the widget, call FinishFullscreenChange to
+      // complete fullscreen change directly.
+      mWindow->FinishFullscreenChange(mFullscreen);
+    }
     // Set observer for the next content paint.
     nsCOMPtr<nsIObserver> observer = new Observer(this);
     nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
@@ -5994,14 +5998,14 @@ MakeWidgetFullscreen(nsGlobalWindow* aWindow, gfx::VRDeviceProxy* aHMD,
   }
   nsCOMPtr<nsIScreen> screen = aHMD ? aHMD->GetScreen() : nullptr;
   if (!performTransition) {
-    aWindow->SetWidgetFullscreen(aReason, aFullscreen, widget, screen);
+    return aWindow->SetWidgetFullscreen(aReason, aFullscreen, widget, screen);
   } else {
     nsCOMPtr<nsIRunnable> task =
       new FullscreenTransitionTask(duration, aWindow, aFullscreen,
                                    widget, screen, transitionData);
     task->Run();
+    return true;
   }
-  return true;
 }
 
 nsresult
@@ -6105,7 +6109,7 @@ nsGlobalWindow::SetFullscreenInternal(FullscreenReason aReason,
   return NS_OK;
 }
 
-void
+bool
 nsGlobalWindow::SetWidgetFullscreen(FullscreenReason aReason, bool aIsFullscreen,
                                     nsIWidget* aWidget, nsIScreen* aScreen)
 {
@@ -6117,13 +6121,12 @@ nsGlobalWindow::SetWidgetFullscreen(FullscreenReason aReason, bool aIsFullscreen
   if (nsCOMPtr<nsIPresShell> presShell = mDocShell->GetPresShell()) {
     presShell->SetIsInFullscreenChange(true);
   }
-  if (aReason == nsPIDOMWindow::eForFullscreenMode) {
+  nsresult rv = aReason == nsPIDOMWindow::eForFullscreenMode ?
     // If we enter fullscreen for fullscreen mode, we want
     // the native system behavior.
-    aWidget->MakeFullScreenWithNativeTransition(aIsFullscreen, aScreen);
-  } else {
+    aWidget->MakeFullScreenWithNativeTransition(aIsFullscreen, aScreen) :
     aWidget->MakeFullScreen(aIsFullscreen, aScreen);
-  }
+  return NS_SUCCEEDED(rv);
 }
 
 /* virtual */ void

dom/base/nsGlobalWindow.h

@@ -473,7 +473,7 @@ public:
     FullscreenReason aReason, bool aIsFullscreen,
     mozilla::gfx::VRDeviceProxy *aHMD = nullptr) override final;
   virtual void FinishFullscreenChange(bool aIsFullscreen) override final;
-  void SetWidgetFullscreen(FullscreenReason aReason, bool aIsFullscreen,
+  bool SetWidgetFullscreen(FullscreenReason aReason, bool aIsFullscreen,
                            nsIWidget* aWidget, nsIScreen* aScreen);
   bool FullScreen() const;
 

widget/nsIWidget.h

@@ -1142,6 +1142,10 @@ class nsIWidget : public nsISupports {
      * if possible.  (If not, it behaves as if aTargetScreen is null.)
      * If !aFullScreen, aTargetScreen is ignored.
      * aTargetScreen support is currently only implemented on Windows.
+     *
+     * @return NS_OK if the widget is setup properly for fullscreen and
+     * FullscreenChanged callback has been or will be called. If other
+     * value is returned, the caller should continue the change itself.
      */
     NS_IMETHOD MakeFullScreen(bool aFullScreen, nsIScreen* aTargetScreen = nullptr) = 0;