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

Source/modules/modules.gypi

 {
   'includes': [
     '../core/core_generated.gypi',
     'modules_generated.gypi',
   ],
   'variables': {
     # Experimental hooks for embedder to provide extra IDL and source files.
     #
     # Note: this is not a supported API. If you rely on this, you will be broken
     # from time to time as the code generator changes in backward incompatible
@@ skipping 634 matching lines @@
       'quota/WorkerNavigatorStorageQuota.cpp',
       'quota/WorkerNavigatorStorageQuota.h',
       'screen_orientation/LockOrientationCallback.cpp',
       'screen_orientation/LockOrientationCallback.h',
       'screen_orientation/ScreenScreenOrientation.cpp',
       'screen_orientation/ScreenScreenOrientation.h',
       'screen_orientation/ScreenOrientation.cpp',
       'screen_orientation/ScreenOrientation.h',
       'screen_orientation/ScreenOrientationController.cpp',
       'screen_orientation/ScreenOrientationController.h',
+      'screen_orientation/ScreenOrientationDispatcher.cpp',
+      'screen_orientation/ScreenOrientationDispatcher.h',
       'serviceworkers/CacheStorage.cpp',
       'serviceworkers/CacheStorage.h',
       'serviceworkers/Client.cpp',
       'serviceworkers/Client.h',
       'serviceworkers/FetchBodyStream.cpp',
       'serviceworkers/FetchBodyStream.h',
       'serviceworkers/FetchEvent.cpp',
       'serviceworkers/FetchEvent.h',
       'serviceworkers/FetchHeaderList.cpp',
       'serviceworkers/FetchHeaderList.h',
@@ skipping 330 matching lines @@
       'serviceworkers/ServiceWorkerContainerTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/NewWebSocketChannelImplTest.cpp',
       'websockets/WebSocketDeflaterTest.cpp',
       'websockets/WebSocketExtensionDispatcherTest.cpp',
       'websockets/WebSocketExtensionParserTest.cpp',
       'websockets/WebSocketPerMessageDeflateTest.cpp',
     ],
   },
 }