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

Source/modules/device_orientation/DeviceOrientationDispatcher.cpp

Index: Source/modules/device_orientation/DeviceOrientationDispatcher.cpp
diff --git a/Source/modules/device_orientation/DeviceOrientationDispatcher.cpp b/Source/modules/device_orientation/DeviceOrientationDispatcher.cpp
index 68050dc59eb67f0d8101c05459b643d1658777af..9896ea31022d6f082718bc875ee492a5bfa3ab9e 100644
--- a/Source/modules/device_orientation/DeviceOrientationDispatcher.cpp
+++ b/Source/modules/device_orientation/DeviceOrientationDispatcher.cpp
@@ -53,12 +53,12 @@ DeviceOrientationDispatcher::~DeviceOrientationDispatcher()
 
 void DeviceOrientationDispatcher::startListening()
 {
-    blink::Platform::current()->setDeviceOrientationListener(this);
+    blink::Platform::current()->startListening(WebPlatformEventDeviceOrientation, this);
 }
 
 void DeviceOrientationDispatcher::stopListening()
 {
-    blink::Platform::current()->setDeviceOrientationListener(0);
+    blink::Platform::current()->stopListening(WebPlatformEventDeviceOrientation);
     m_lastDeviceOrientationData.clear();
 }