Implement MediaSession on top of the WebMediaPlayerDelegate.

content/renderer/media/renderer_webmediaplayer_delegate.h

Index: content/renderer/media/renderer_webmediaplayer_delegate.h
diff --git a/content/renderer/media/renderer_webmediaplayer_delegate.h b/content/renderer/media/renderer_webmediaplayer_delegate.h
index 3b1e3560e5d0995aa846cfa99daf8a17da11a32c..843a7b78294c34f60184daaf0c823ff2cc5e0b1b 100644
--- a/content/renderer/media/renderer_webmediaplayer_delegate.h
+++ b/content/renderer/media/renderer_webmediaplayer_delegate.h
@@ -27,22 +27,37 @@ class RendererWebMediaPlayerDelegate
   explicit RendererWebMediaPlayerDelegate(content::RenderFrame* render_frame);
   ~RendererWebMediaPlayerDelegate() override;
 
+  // Returns the player id for a given observer.
+  // TODO(dalecurtis): Remove once RendererWebMediaPlayerManager is removed.
+  static int64_t GetPlayerId(Observer* observer);
+
   // Returns true if this RenderFrame has ever seen media playback before.
   bool has_played_media() const { return has_played_media_; }
 
   // WebMediaPlayerDelegate implementation.
-  void DidPlay(blink::WebMediaPlayer* player) override;
-  void DidPause(blink::WebMediaPlayer* player) override;
-  void PlayerGone(blink::WebMediaPlayer* player) override;
   void AddObserver(Observer* observer) override;
   void RemoveObserver(Observer* observer) override;
+  void DidPlay(Observer* observer,
+               bool has_video,
+               bool has_audio,
+               bool is_remote,
+               base::TimeDelta duration) override;
+  void DidPause(Observer* observer, bool reached_end_of_stream) override;
+  void PlayerGone(Observer* observer) override;
   bool IsHidden() override;
 
   // content::RenderFrameObserver overrides.
   void WasHidden() override;
   void WasShown() override;
+  bool OnMessageReceived(const IPC::Message& msg) override;
 
  private:
+  bool GetObserver(int64_t player_cookie, Observer** observer);
+  void OnMediaDelegatePause(int64_t player_cookie);
+  void OnMediaDelegatePlay(int64_t player_cookie);
+  void OnMediaDelegateVolumeMultiplierUpdate(int64_t player_cookie,
+                                             double multiplier);
+
   bool has_played_media_ = false;
   base::ObserverList<Observer> observer_list_;