Introduce PlatformEvent to handle Device events, Battery events and Gamepad events.

Source/modules/gamepad/NavigatorGamepad.h

Index: Source/modules/gamepad/NavigatorGamepad.h
diff --git a/Source/modules/gamepad/NavigatorGamepad.h b/Source/modules/gamepad/NavigatorGamepad.h
index 07b153660e078d891c5aba69320a31cafc25cea3..c51b121effe23cefaeb6e6f45eef41f75dc859cf 100644
--- a/Source/modules/gamepad/NavigatorGamepad.h
+++ b/Source/modules/gamepad/NavigatorGamepad.h
@@ -28,7 +28,7 @@
 
 #include "core/frame/DOMWindowLifecycleObserver.h"
 #include "core/frame/DOMWindowProperty.h"
-#include "core/frame/DeviceEventControllerBase.h"
+#include "core/frame/PlatformEventController.h"
 #include "platform/AsyncMethodRunner.h"
 #include "platform/Supplementable.h"
 #include "platform/heap/Handle.h"
@@ -47,7 +47,7 @@ class GamepadList;
 class Navigator;
 class WebKitGamepadList;
 
-class NavigatorGamepad FINAL : public NoBaseWillBeGarbageCollectedFinalized<NavigatorGamepad>, public WillBeHeapSupplement<Navigator>, public DOMWindowProperty, public DeviceEventControllerBase, public DOMWindowLifecycleObserver {
+class NavigatorGamepad FINAL : public NoBaseWillBeGarbageCollectedFinalized<NavigatorGamepad>, public WillBeHeapSupplement<Navigator>, public DOMWindowProperty, public PlatformEventController, public DOMWindowLifecycleObserver {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(NavigatorGamepad);
 public:
     static NavigatorGamepad* from(Document&);
@@ -76,7 +76,7 @@ private:
     virtual void willDestroyGlobalObjectInFrame() OVERRIDE;
     virtual void willDetachGlobalObjectFromFrame() OVERRIDE;
 
-    // DeviceEventControllerBase
+    // PlatformEventController
     virtual void registerWithDispatcher() OVERRIDE;
     virtual void unregisterWithDispatcher() OVERRIDE;
     virtual bool hasLastData() OVERRIDE;