Implement MediaSession on top of the WebMediaPlayerDelegate.

media/blink/webmediaplayer_impl.h

Index: media/blink/webmediaplayer_impl.h
diff --git a/media/blink/webmediaplayer_impl.h b/media/blink/webmediaplayer_impl.h
index ba03528cde0586e5ed147673922c16c0f41b3545..ca1bf3f435c046d5c7d22a5adef96e9c85384e28 100644
--- a/media/blink/webmediaplayer_impl.h
+++ b/media/blink/webmediaplayer_impl.h
@@ -194,6 +194,9 @@ class MEDIA_BLINK_EXPORT WebMediaPlayerImpl
   // WebMediaPlayerDelegate::Observer implementation.
   void OnHidden() override;
   void OnShown() override;
+  void OnPlay() override;
+  void OnPause() override;
+  void OnVolumeMultiplierUpdate(double multiplier) override;
 
 #if defined(OS_ANDROID)  // WMPI_CAST
   bool isRemote() const override;
@@ -386,6 +389,7 @@ class MEDIA_BLINK_EXPORT WebMediaPlayerImpl
   blink::WebMediaPlayerEncryptedMediaClient* encrypted_client_;
 
   base::WeakPtr<WebMediaPlayerDelegate> delegate_;
+  int delegate_id_;

[sandersd (OOO until July 31), 2016/01/25 19:10:59]

Nit: Document |delegate_id_|.

[DaleCurtis, 2016/01/25 21:49:47]

Done.

 
   WebMediaPlayerParams::DeferLoadCB defer_load_cb_;
   WebMediaPlayerParams::Context3DCB context_3d_cb_;
@@ -434,6 +438,9 @@ class MEDIA_BLINK_EXPORT WebMediaPlayerImpl
   WebMediaPlayerCast cast_impl_;
 #endif
 
+  double volume_;
+  double volume_multiplier_;

[sandersd (OOO until July 31), 2016/01/25 19:10:59]

Nit: Document |volume_multiplier_|, it's not obvious from context.

[DaleCurtis, 2016/01/25 21:49:47]

Done.

+
   scoped_ptr<RendererFactory> renderer_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebMediaPlayerImpl);