Make Screen Orientation use Platform Events in order to handle polling.

Source/modules/screen_orientation/ScreenOrientationController.h

Index: Source/modules/screen_orientation/ScreenOrientationController.h
diff --git a/Source/modules/screen_orientation/ScreenOrientationController.h b/Source/modules/screen_orientation/ScreenOrientationController.h
index 8c22be07397760319684f790c17a7f15b4a91292..f3322662c2098982d8d6ff4a5e734cfbdbe4e218 100644
--- a/Source/modules/screen_orientation/ScreenOrientationController.h
+++ b/Source/modules/screen_orientation/ScreenOrientationController.h
@@ -5,7 +5,7 @@
 #ifndef ScreenOrientationController_h
 #define ScreenOrientationController_h
 
-#include "core/page/PageLifecycleObserver.h"
+#include "core/frame/PlatformEventController.h"
 #include "platform/Supplementable.h"
 #include "platform/Timer.h"
 #include "public/platform/WebLockOrientationCallback.h"
@@ -24,7 +24,7 @@ class ScreenOrientation;
 class ScreenOrientationController FINAL
     : public NoBaseWillBeGarbageCollectedFinalized<ScreenOrientationController>
     , public WillBeHeapSupplement<LocalFrame>
-    , public PageLifecycleObserver {
+    , public PlatformEventController {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(ScreenOrientationController);
     WTF_MAKE_NONCOPYABLE(ScreenOrientationController);
 public:
@@ -50,9 +50,15 @@ private:
     explicit ScreenOrientationController(LocalFrame&, blink::WebScreenOrientationClient*);
     static blink::WebScreenOrientationType computeOrientation(FrameView*);
 
-    // Inherited from PageLifecycleObserver.
+    // Inherited from PlatformEventController.
+    virtual void didUpdateData() OVERRIDE;
+    virtual void registerWithDispatcher() OVERRIDE;
+    virtual void unregisterWithDispatcher() OVERRIDE;
+    virtual bool hasLastData() OVERRIDE;
     virtual void pageVisibilityChanged() OVERRIDE;
 
+    void notifyDispatcher();
+
     void updateOrientation();
 
     void dispatchEventTimerFired(Timer<ScreenOrientationController>*);