Plumb audio focus support for spitzer clients.

content/browser/media/android/media_web_contents_observer_android.h

 // Copyright 2016 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_MEDIA_WEB_CONTENTS_OBSERVER_ANDROID_H_
 #define CONTENT_BROWSER_MEDIA_ANDROID_MEDIA_WEB_CONTENTS_OBSERVER_ANDROID_H_
 
 #include <stdint.h>
 
+#include <list>
+
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "content/browser/media/media_web_contents_observer.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 class BrowserCdmManager;
 class BrowserMediaPlayerManager;
@@ skipping 31 matching lines @@
 
 #if defined(VIDEO_HOLE)
   void OnFrameInfoUpdated();
 #endif  // defined(VIDEO_HOLE)
 
   // MediaWebContentsObserverAndroid overrides.
   void RenderFrameDeleted(RenderFrameHost* render_frame_host) override;
   bool OnMessageReceived(const IPC::Message& message,
                          RenderFrameHost* render_frame_host) override;
 
+ protected:
+  void WaitForAudioFocusAsyncInternal(int render_frame_id,

[mlamouri (slow - plz ping), 2016/02/03 15:20:52]

Add comment saying that `callback` may never be called if the frame associated
with `render_frame_id` is deleted.

+                                      const base::Closure& focus_cb) override;

[mlamouri (slow - plz ping), 2016/02/03 15:20:52]

nit: `callback`

+
  private:
   // Handles messages from the WebMediaPlayerDelegate; does not modify the
   // handled state since the superclass needs to handle these as well.
   void OnMediaPlayerDelegateMessageReceived(const IPC::Message& msg,
                                             RenderFrameHost* render_frame_host);
   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,
@@ skipping 24 matching lines @@
 
   // Map from RenderFrameHost* to BrowserMediaSessionManager.
   using MediaSessionManagerMap =
       base::ScopedPtrHashMap<RenderFrameHost*,
                              scoped_ptr<BrowserMediaSessionManager>>;
   MediaSessionManagerMap media_session_managers_;
 
   // Map of renderer process media players to session controllers.
   using MediaSessionMap =
       std::map<MediaPlayerId, scoped_ptr<MediaSessionController>>;
   MediaSessionMap media_session_map_;

[mlamouri (slow - plz ping), 2016/02/03 15:20:52]

I was confused by your change because `media_session_map_` looks like a map of
all the media sessions but it's actually a map of all the controllers. Maybe
worth fixing in a follow-up?

 
+  // List of focus callbacks awaiting fulfillment; each entry is a render frame
+  // id and callback.  There may be multiple entries per render frame id.
+  using FocusWaiter = std::pair<int, base::Closure>;

[mlamouri (slow - plz ping), 2016/02/03 15:20:52]

nit: `using FocusCallback`? or `FocusCallbackWrapper`?

+  std::list<FocusWaiter> focus_waiters_;

[mlamouri (slow - plz ping), 2016/02/03 15:20:52]

nit: focus_callbacks_

+
   DISALLOW_COPY_AND_ASSIGN(MediaWebContentsObserverAndroid);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_ANDROID_MEDIA_WEB_CONTENTS_OBSERVER_ANDROID_H_