Throttle media decoding after excessive Android media server crashes

content/browser/media/android/browser_media_player_manager.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_MEDIA_ANDROID_BROWSER_MEDIA_PLAYER_MANAGER_H_
 #define CONTENT_BROWSER_MEDIA_ANDROID_BROWSER_MEDIA_PLAYER_MANAGER_H_
 
+#include <map>
+
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "base/time/time.h"
 #include "content/browser/android/content_video_view.h"
 #include "content/browser/media/android/media_session_observer.h"
 #include "content/common/content_export.h"
 #include "content/common/media/media_player_messages_enums_android.h"
 #include "content/public/browser/android/content_view_core.h"
@@ skipping 135 matching lines @@
   // Helper function to send messages to RenderFrameObserver.
   bool Send(IPC::Message* msg);
 
  private:
   // Constructs a MediaPlayerAndroid object.
   media::MediaPlayerAndroid* CreateMediaPlayer(
       const MediaPlayerHostMsg_Initialize_Params& media_player_params,
       bool hide_url_log,
       BrowserDemuxerAndroid* demuxer);
 
-  // MediaPlayerAndroid must call this before it is going to decode
-  // media streams. This helps the manager object maintain an array
-  // of active MediaPlayerAndroid objects and release the resources
-  // when needed. Currently we only count video resources as they are
-  // constrained by hardware and memory limits.
-  virtual void OnMediaResourcesRequested(int player_id);
+  // Called to request decoder resources. Returns true if the request is
+  // permitted, or false otherwise. The manager object maintain an array

[Ted C, 2015/09/28 22:42:29]

maintain[s]

[qinmin, 2015/09/29 23:16:22]

Done.

+  // of active MediaPlayerAndroid objects and release the inactive resources

[Ted C, 2015/09/28 22:42:29]

release[s]

[qinmin, 2015/09/29 23:16:22]

Done.

+  // when needed.
+  virtual bool RequestDecoderResources(int player_id, bool temporary);

[Ted C, 2015/09/28 22:42:29]

Can you describe what temporary means and why you should use it?

[qinmin, 2015/09/29 23:16:22]

Done.

 
-  // Called when a player releases all decoding resources.
-  void ReleaseMediaResources(int player_id);
+  // MediaPlayerAndroid must call this to inform the manager that it is about
+  // to release itself.

[Ted C, 2015/09/28 22:42:29]

What is the difference between this and ReleasePlayer below?  Must this always
be called first?

They are very similarly named, so I'm thinking some further explanation would be
nice.  (for example, this sounds like it should be called from within
ReleasePlayer below for consumption by subclasses, but I don't know if that is
the actually true).

[qinmin, 2015/09/29 23:16:22]

Renamed OnPlayerReleased to OnDecoderResourcesReleased, and added more comments
here.

+  virtual void OnPlayerReleased(int player_id);
 
   // Releases the player. However, don't remove it from |players_|.
   void ReleasePlayer(media::MediaPlayerAndroid* player);
 
+  // Called when user approves media playback after being throttled.
+  void OnPlaybackPermissionGranted(int player_id, bool granted);
+
+  // Helper method to start playback.
+  void StartInternal(int player_id);
+
 #if defined(VIDEO_HOLE)
   void ReleasePlayerOfExternalVideoSurfaceIfNeeded(int future_player);
   void OnRequestExternalSurface(int player_id, const gfx::RectF& rect);
+  void ReleaseExternalSurface(int player_id);
 #endif  // defined(VIDEO_HOLE)
 
   RenderFrameHost* const render_frame_host_;
 
   // An array of managed players.
   ScopedVector<media::MediaPlayerAndroid> players_;
 
+  typedef std::map<int, bool> ActivePlayerMap;
+  // Players that have requested decoding resources. Even though resource is
+  // requested, a player may be in a paused or error state and the manager
+  // will release its resources later.
+  ActivePlayerMap active_players_;
+
   // The fullscreen video view object or NULL if video is not played in
   // fullscreen.
   scoped_ptr<ContentVideoView> video_view_;
 
 #if defined(VIDEO_HOLE)
   scoped_ptr<ExternalVideoSurfaceContainer> external_video_surface_container_;
 #endif
 
   // Player ID of the fullscreen media player.
   int fullscreen_player_id_;
 
   // Whether the fullscreen player has been Release()-d.
   bool fullscreen_player_is_released_;
 
   WebContents* const web_contents_;
 
   // Object for retrieving resources media players.
   scoped_ptr<media::MediaResourceGetter> media_resource_getter_;
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<BrowserMediaPlayerManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserMediaPlayerManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_ANDROID_BROWSER_MEDIA_PLAYER_MANAGER_H_