NOT FOR LANDING Introduce and use WebMediaSession

Source/core/loader/FrameLoaderClient.h

Index: Source/core/loader/FrameLoaderClient.h
diff --git a/Source/core/loader/FrameLoaderClient.h b/Source/core/loader/FrameLoaderClient.h
index c522c95f276dc38fc889537de97939f778e37656..7db897eee512e44b8ac213f47f24fce773cc8e70 100644
--- a/Source/core/loader/FrameLoaderClient.h
+++ b/Source/core/loader/FrameLoaderClient.h
@@ -69,6 +69,7 @@ class WebApplicationCacheHostClient;
 class WebCookieJar;
 class WebMediaPlayer;
 class WebMediaPlayerClient;
+class WebMediaSession;
 class WebRTCPeerConnectionHandler;
 class WebServiceWorkerProvider;
 class WebSocketHandle;
@@ -161,6 +162,8 @@ public:
 
     virtual PassOwnPtr<WebMediaPlayer> createWebMediaPlayer(HTMLMediaElement&, const WebURL&, WebMediaPlayerClient*) = 0;
 
+    virtual PassOwnPtr<WebMediaSession> createWebMediaSession() = 0;
+
     virtual ObjectContentType objectContentType(const KURL&, const String& mimeType, bool shouldPreferPlugInsForImages) = 0;
 
     virtual void didCreateNewDocument() = 0;