Allow MediaSession in iframes to be routed

content/browser/media/session/media_session_impl.h

Index: content/browser/media/session/media_session_impl.h
diff --git a/content/browser/media/session/media_session_impl.h b/content/browser/media/session/media_session_impl.h
index 1f1a0fc85d172fd45655d48251e7ee86ac05bae3..663bb96d6cb8ad67a3bccc2de8968cd8b53ba6af 100644
--- a/content/browser/media/session/media_session_impl.h
+++ b/content/browser/media/session/media_session_impl.h
@@ -7,6 +7,8 @@
 
 #include <stddef.h>
 
+#include <set>
+
 #include "base/callback_list.h"
 #include "base/id_map.h"
 #include "base/macros.h"
@@ -39,7 +41,7 @@ class MediaSessionImplStateObserver;
 class MediaSessionImplVisibilityBrowserTest;
 class MediaSessionObserver;
 class MediaSessionPlayerObserver;
-class MediaSessionServiceImpl;
+class MediaSessionServiceRouter;
 
 #if defined(OS_ANDROID)
 class MediaSessionAndroid;
@@ -84,8 +86,10 @@ class MediaSessionImpl : public MediaSession,
   void AddObserver(MediaSessionObserver* observer);
   void RemoveObserver(MediaSessionObserver* observer);
 
-  void SetMetadata(const base::Optional<MediaMetadata>& metadata);
-  const base::Optional<MediaMetadata>& metadata() const { return metadata_; }
+  void NotifyMediaSessionMetadataChange(
+      const base::Optional<MediaMetadata>& metadata);
+  void NotifyMediaSessionActionsChange(
+      const std::set<blink::mojom::MediaSessionAction>& actions);
 
   // Adds the given player to the current media session. Returns whether the
   // player was successfully added. If it returns false, AddPlayer() should be
@@ -127,13 +131,10 @@ class MediaSessionImpl : public MediaSession,
   // Received a media session action and forward to blink::MediaSession.
   void DidReceiveAction(blink::mojom::MediaSessionAction action) override;
 
-  // Called when an action is enabled in blink::MediaSession. This method will
-  // notify the observers that the action is enabled.
-  void OnMediaSessionEnabledAction(blink::mojom::MediaSessionAction action);
-
-  // Called when an action is disabled in blink::MediaSession. This method will
-  // notify the observers that the action is disabled.
-  void OnMediaSessionDisabledAction(blink::mojom::MediaSessionAction action);
+  // Called when blink::MediaSession action list has changed. This method will
+  // notify the observers of the change.
+  void OnMediaSessionActionsChanged(
+      const std::set<blink::mojom::MediaSessionAction>& actions);
 
   // Let the media session start ducking such that the volume multiplier is
   // reduced.
@@ -172,10 +173,13 @@ class MediaSessionImpl : public MediaSession,
   // WebContentsObserver implementation
   void WebContentsDestroyed() override;
 
-  // Sets the associated MediaSessionService for communicating with
+  // Getting the associated MediaSessionServiceRouter for communicating with
   // blink::MediaSession.
-  MediaSessionServiceImpl* GetMediaSessionService() { return service_; }
-  void SetMediaSessionService(MediaSessionServiceImpl* service);
+  MediaSessionServiceRouter* GetMediaSessionServiceRouter() {
+    return service_router_.get();
+  }
+
+  MediaSessionPlayerObserver* GetMostMeaningfulPlayerObserver();
 
  private:
   friend class content::WebContentsUserData<MediaSessionImpl>;
@@ -267,7 +271,6 @@ class MediaSessionImpl : public MediaSession,
   // StopDucking().
   bool is_ducking_;
 
-  base::Optional<MediaMetadata> metadata_;
   base::CallbackList<void(State)> media_session_state_listeners_;
 
   base::ObserverList<MediaSessionObserver> observers_;
@@ -278,7 +281,7 @@ class MediaSessionImpl : public MediaSession,
 
   // The MediaSessionService this session is associated with (the service of the
   // top-level frame).
-  MediaSessionServiceImpl* service_;
+  std::unique_ptr<MediaSessionServiceRouter> service_router_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaSessionImpl);
 };