Media Session API: make MediaMetadata mutable.

third_party/WebKit/Source/modules/mediasession/MediaSession.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MediaSession_h
 #define MediaSession_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/dom/ContextLifecycleObserver.h"
 #include "core/events/EventTarget.h"
@@ skipping 21 matching lines @@
 
   void dispose();
 
   void setMetadata(MediaMetadata*);
   MediaMetadata* metadata() const;
 
   // EventTarget implementation.
   const WTF::AtomicString& interfaceName() const override;
   ExecutionContext* getExecutionContext() const override;
 
+  // Called by the MediaMetadata owned by |this| when it has updates. Also used
+  // internally when a new MediaMetadata object is set.
+  void onMetadataChanged();
+
   DEFINE_ATTRIBUTE_EVENT_LISTENER(play);
   DEFINE_ATTRIBUTE_EVENT_LISTENER(pause);
   DEFINE_ATTRIBUTE_EVENT_LISTENER(playpause);
   DEFINE_ATTRIBUTE_EVENT_LISTENER(previoustrack);
   DEFINE_ATTRIBUTE_EVENT_LISTENER(nexttrack);
   DEFINE_ATTRIBUTE_EVENT_LISTENER(seekforward);
   DEFINE_ATTRIBUTE_EVENT_LISTENER(seekbackward);
 
   DECLARE_VIRTUAL_TRACE();
 
@@ skipping 18 matching lines @@
   mojom::blink::MediaSessionService* getService();
 
   Member<MediaMetadata> m_metadata;
   mojom::blink::MediaSessionServicePtr m_service;
   mojo::Binding<blink::mojom::blink::MediaSessionClient> m_clientBinding;
 };
 
 }  // namespace blink
 
 #endif  // MediaSession_h