Letting Flash join MediaSession (stack implementaion)

content/browser/media/session/media_session.h

Index: content/browser/media/session/media_session.h
diff --git a/content/browser/media/session/media_session.h b/content/browser/media/session/media_session.h
index 1cb78315bc5f4bd4e9a05600e55c6c9a5f085094..ba796b7d74736ef0353b8635ef0a299a0c33c48b 100644
--- a/content/browser/media/session/media_session.h
+++ b/content/browser/media/session/media_session.h
@@ -58,12 +58,21 @@ class MediaSession : public WebContentsObserver,
     CONTENT,
   };
 
+  // Only visible to tests.
+  enum class State {
+    ACTIVE,
+    SUSPENDED,
+    INACTIVE
+  };
+
   // Returns the MediaSession associated to this WebContents. Creates one if
   // none is currently available.
   CONTENT_EXPORT static MediaSession* Get(WebContents* web_contents);
 
   ~MediaSession() override;
 
+  void WasShown() override;

[whywhat, 2016/09/13 00:16:17]

nit: unused.

[Zhiqiang Zhang (Slow), 2016/09/22 12:30:33]

Done.

+
   void SetMetadata(const base::Optional<MediaMetadata>& metadata);
   const base::Optional<MediaMetadata>& metadata() const { return metadata_; }
 
@@ -112,6 +121,8 @@ class MediaSession : public WebContentsObserver,
   // recovered.
   CONTENT_EXPORT void StopDucking();
 
+  CONTENT_EXPORT bool IsDucking() { return is_ducking_; }

[whywhat, 2016/09/13 00:16:17]

nit: ditto

[Zhiqiang Zhang (Slow), 2016/09/22 12:30:33]

Done.

+
   // Returns if the session can be controlled by Resume() and Suspend calls
   // above.
   CONTENT_EXPORT bool IsControllable() const;
@@ -129,6 +140,11 @@ class MediaSession : public WebContentsObserver,
   // Returns if the session is currently suspended or inactive.
   CONTENT_EXPORT bool IsSuspended() const;
 
+  void AllowPepperOverrideDucking();
+  void DisallowPepperOverrideDucking();
+
+  bool HasPepper() const;
+
  private:
   friend class content::WebContentsUserData<MediaSession>;
   friend class ::MediaSessionBrowserTest;
@@ -144,12 +160,6 @@ class MediaSession : public WebContentsObserver,
   CONTENT_EXPORT void RemoveAllPlayersForTest();
   CONTENT_EXPORT MediaSessionUmaHelper* uma_helper_for_test();
 
-  enum class State {
-    ACTIVE,
-    SUSPENDED,
-    INACTIVE
-  };
-
   // Representation of a player for the MediaSession.
   struct PlayerIdentifier {
     PlayerIdentifier(MediaSessionObserver* observer, int player_id);
@@ -199,14 +209,19 @@ class MediaSession : public WebContentsObserver,
   // Get the volume multiplier, which depends on whether the media session is
   // ducking.
   double GetVolumeMultiplier() const;
+  double GetPepperVolumeMultiplier() const;
 
   // Registers a MediaSession state change callback.
   CONTENT_EXPORT std::unique_ptr<base::CallbackList<void(State)>::Subscription>
   RegisterMediaSessionStateChangedCallbackForTest(
       const StateChangedCallback& cb);
 
+  CONTENT_EXPORT bool AddPepperPlayer(MediaSessionObserver* observer,
+                                      int player_id);
+
   std::unique_ptr<MediaSessionDelegate> delegate_;
   PlayersMap players_;
+  PlayersMap pepper_players_;
 
   State audio_focus_state_;
   SuspendType suspend_type_;
@@ -218,6 +233,9 @@ class MediaSession : public WebContentsObserver,
   // is set to |true| after StartDucking(), and will be set to |false| after
   // StopDucking().
   bool is_ducking_;
+  // Whether allow pepper to override ducking (play in full volume) when the
+  // session is not active.
+  bool allow_pepper_override_ducking_;
 
   base::Optional<MediaMetadata> metadata_;
   base::CallbackList<void(State)> media_session_state_listeners_;