Move PlatformEventDispatcher implementations to the Oilpan heap.

Source/modules/screen_orientation/ScreenOrientationDispatcher.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ScreenOrientationDispatcher_h
 #define ScreenOrientationDispatcher_h
 
 #include "core/frame/PlatformEventDispatcher.h"
+#include "platform/heap/Handle.h"
 
 namespace blink {
 
-class FrameView;
-class ScreenOrientation;
-
 // ScreenOrientationDispatcher is a singleton that handles whether the current
 // Blink instance should be listening to the screen orientation platform events.
 // It is not a common implementation of PlatformEventDispatcher in the sense
 // that it doesn't actually dispatch events but simply start/stop listening. The
 // reason being that screen orientation events are always sent to the WebFrame's
 // but some platforms require to poll to have an accurate reporting. When
 // ScreenOrientationDispatcher is listening, that means that the platform should
 // be polling if required.
-class ScreenOrientationDispatcher FINAL :
-    public PlatformEventDispatcher {
+class ScreenOrientationDispatcher final : public GarbageCollectedFinalized<ScreenOrientationDispatcher>, public PlatformEventDispatcher {
 public:
     static ScreenOrientationDispatcher& instance();
 
+    virtual void trace(Visitor*) override;
+
 private:
     ScreenOrientationDispatcher();
-    virtual ~ScreenOrientationDispatcher();
 
     // Inherited from PlatformEventDispatcher.
     virtual void startListening() OVERRIDE;
     virtual void stopListening() OVERRIDE;
 };
 
 } // namespace blink
 
 #endif // ScreenOrientationDispatcher_h