Convert FullscreenController to use WebCallbacks

third_party/WebKit/Source/core/dom/Fullscreen.h

Index: third_party/WebKit/Source/core/dom/Fullscreen.h
diff --git a/third_party/WebKit/Source/core/dom/Fullscreen.h b/third_party/WebKit/Source/core/dom/Fullscreen.h
index f14a4b628374aa9fe36484277804bb323d3e62f7..db12cea5d9916c08f5ad800693ca928b585b3b35 100644
--- a/third_party/WebKit/Source/core/dom/Fullscreen.h
+++ b/third_party/WebKit/Source/core/dom/Fullscreen.h
@@ -92,9 +92,8 @@ class CORE_EXPORT Fullscreen final
                : nullptr;
   }
 
-  // Called by FullscreenController to notify that we've entered or exited
-  // fullscreen. All frames are notified, so there may be no pending request.
-  void didEnterFullscreen();
+  // Called by FullscreenController to notify that we've exited fullscreen. All
+  // frames are notified, so there may be no fullscreen element.
   void didExitFullscreen();
 
   void setFullScreenLayoutObject(LayoutFullScreen*);
@@ -125,12 +124,16 @@ class CORE_EXPORT Fullscreen final
   DECLARE_VIRTUAL_TRACE();
 
  private:
+  friend class RequestFullscreenCallbacks;
+
   static Fullscreen* fromIfExistsSlow(Document&);
 
   explicit Fullscreen(Document&);
 
   Document* document();
 
+  void didEnterFullscreen(Element&);
+
   void clearFullscreenElementStack();
   void popFullscreenElementStack();
   void pushFullscreenElementStack(Element&, RequestType);
@@ -139,7 +142,6 @@ class CORE_EXPORT Fullscreen final
   void enqueueErrorEvent(Element&, RequestType);
   void eventQueueTimerFired(TimerBase*);
 
-  Member<Element> m_pendingFullscreenElement;
   HeapVector<std::pair<Member<Element>, RequestType>> m_fullscreenElementStack;
   Member<Element> m_currentFullScreenElement;
   LayoutFullScreen* m_fullScreenLayoutObject;