[MediaSession] Add playbackState attribute to Blink MediaSession and use it to determine playback s…

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

Index: third_party/WebKit/Source/modules/mediasession/MediaSession.h
diff --git a/third_party/WebKit/Source/modules/mediasession/MediaSession.h b/third_party/WebKit/Source/modules/mediasession/MediaSession.h
index bf7fb750d1d5ba3d746a7357a2dda86187d3dfb0..022315412f6eb09c72406d9a0c13a5e15ddac1d0 100644
--- a/third_party/WebKit/Source/modules/mediasession/MediaSession.h
+++ b/third_party/WebKit/Source/modules/mediasession/MediaSession.h
@@ -32,6 +32,9 @@ class MODULES_EXPORT MediaSession final
 
   void dispose();
 
+  void setPlaybackState(const String&);
+  String playbackState();
+
   void setMetadata(MediaMetadata*);
   MediaMetadata* metadata() const;
 
@@ -69,6 +72,7 @@ class MODULES_EXPORT MediaSession final
   // Returns null when the ExecutionContext is not document.
   mojom::blink::MediaSessionService* getService();
 
+  mojom::blink::MediaSessionPlaybackState m_playbackState;
   Member<MediaMetadata> m_metadata;
   mojom::blink::MediaSessionServicePtr m_service;
   mojo::Binding<blink::mojom::blink::MediaSessionClient> m_clientBinding;