Move PlatformEventDispatcher implementations to the Oilpan heap.

Source/modules/screen_orientation/ScreenOrientationDispatcher.h

Index: Source/modules/screen_orientation/ScreenOrientationDispatcher.h
diff --git a/Source/modules/screen_orientation/ScreenOrientationDispatcher.h b/Source/modules/screen_orientation/ScreenOrientationDispatcher.h
index 5fef6c68c55f849bacdcc509a9a4c923e0f67f8c..efa34ee6dbe7a57c028ec97ef72f1235db887f63 100644
--- a/Source/modules/screen_orientation/ScreenOrientationDispatcher.h
+++ b/Source/modules/screen_orientation/ScreenOrientationDispatcher.h
@@ -6,12 +6,10 @@
 #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
@@ -20,14 +18,14 @@ class ScreenOrientation;
 // 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 GarbageCollected<ScreenOrientationDispatcher>, public PlatformEventDispatcher {
 public:
     static ScreenOrientationDispatcher& instance();
 
+    virtual void trace(Visitor*) override;
+
 private:
     ScreenOrientationDispatcher();
-    virtual ~ScreenOrientationDispatcher();
 
     // Inherited from PlatformEventDispatcher.
     virtual void startListening() OVERRIDE;