NOT FOR LANDING Introduce and use WebMediaSession

Source/core/loader/EmptyClients.h

 /*
  * Copyright (C) 2006 Eric Seidel (eric@webkit.org)
  * Copyright (C) 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 215 matching lines @@
     bool navigateBackForward(int offset) const override { return false; }
     void didDisplayInsecureContent() override {}
     void didRunInsecureContent(SecurityOrigin*, const KURL&) override {}
     void didDetectXSS(const KURL&, bool) override {}
     void didDispatchPingLoader(const KURL&) override {}
     void selectorMatchChanged(const Vector<String>&, const Vector<String>&) override {}
     PassRefPtrWillBeRawPtr<LocalFrame> createFrame(const FrameLoadRequest&, const AtomicString&, HTMLFrameOwnerElement*) override;
     PassRefPtrWillBeRawPtr<Widget> createPlugin(HTMLPlugInElement*, const KURL&, const Vector<String>&, const Vector<String>&, const String&, bool, DetachedPluginPolicy) override;
     bool canCreatePluginWithoutRenderer(const String& mimeType) const override { return false; }
     PassOwnPtr<WebMediaPlayer> createWebMediaPlayer(HTMLMediaElement&, const WebURL&, WebMediaPlayerClient*) override;
+    PassOwnPtr<WebMediaSession> createWebMediaSession() override;
 
     ObjectContentType objectContentType(const KURL&, const String&, bool) override { return ObjectContentType(); }
 
     void didCreateNewDocument() override {}
     void dispatchDidClearWindowObjectInMainWorld() override {}
     void documentElementAvailable() override {}
 
     void didCreateScriptContext(v8::Local<v8::Context>, int extensionGroup, int worldId) override {}
     void willReleaseScriptContext(v8::Local<v8::Context>, int worldId) override {}
     bool allowScriptExtension(const String& extensionName, int extensionGroup, int worldId) override { return false; }
@@ skipping 76 matching lines @@
     ~EmptyDragClient() override {}
     DragDestinationAction actionMaskForDrag(DragData*) override { return DragDestinationActionNone; }
     void startDrag(DragImage*, const IntPoint&, const IntPoint&, DataTransfer*, LocalFrame*, bool) override {}
 };
 
 CORE_EXPORT void fillWithEmptyClients(Page::PageClients&);
 
 } // namespace blink
 
 #endif // EmptyClients_h