Plumb audio focus support for spitzer clients.

content/browser/media/media_web_contents_observer.h

 // Copyright 2014 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_MEDIA_WEB_CONTENTS_OBSERVER_H_
 #define CONTENT_BROWSER_MEDIA_MEDIA_WEB_CONTENTS_OBSERVER_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <set>
 #include <vector>
 
+#include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/web_contents_observer.h"
 
 namespace content {
 class PowerSaveBlocker;
 
 // This class manages all RenderFrame based media related managers at the
 // browser side. It receives IPC messages from media RenderFrameObservers and
@@ skipping 16 matching lines @@
   void WasHidden() override;
 
   bool has_audio_power_save_blocker_for_testing() const {
     return !!audio_power_save_blocker_;
   }
 
   bool has_video_power_save_blocker_for_testing() const {
     return !!video_power_save_blocker_;
   }
 
+  // Executes |focus_cb| on the calling thread once the given render frame has
+  // audio focus.  Clients are responsible for invalidating |focus_cb| if their
+  // lifetime changes or the callback is unnecessary.
+  //
+  // This call does not request focus, it only waits for a focus request for the
+  // given render frame to be approved.  The focus request must be initiated via
+  // the WebMediaPlayerDelegate interface in the renderer.
+  //
+  // Focus is never denied, only delayed until the underlying platform approves
+  // the request.  |focus_cb| may never be called if the given render frame goes
+  // away.  Callers are expected to have their own monitoring for such events in
+  // order to properly handle the lack of a callback.
+  static void WaitForAudioFocusAsync(int render_process_id,
+                                     int render_frame_id,
+                                     const base::Closure& focus_cb);
+
+ protected:
+  virtual void WaitForAudioFocusAsyncInternal(int render_frame_id,
+                                              const base::Closure& focus_cb);
+
  private:
   void OnMediaDestroyed(RenderFrameHost* render_frame_host, int delegate_id);
   void OnMediaPaused(RenderFrameHost* render_frame_host,
                      int delegate_id,
                      bool reached_end_of_stream);
   void OnMediaPlaying(RenderFrameHost* render_frame_host,
                       int delegate_id,
                       bool has_video,
                       bool has_audio,
                       bool is_remote,
@@ skipping 30 matching lines @@
   ActiveMediaPlayerMap active_video_players_;
   scoped_ptr<PowerSaveBlocker> audio_power_save_blocker_;
   scoped_ptr<PowerSaveBlocker> video_power_save_blocker_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaWebContentsObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_MEDIA_WEB_CONTENTS_OBSERVER_H_