Implement one-shot audio focus inside MediaSession

content/browser/media/session/pepper_playback_observer.cc

 // 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.
 
 #include "content/browser/media/session/pepper_playback_observer.h"
 
 #include "base/feature_list.h"
 #include "base/metrics/histogram_macros.h"
 #include "content/browser/media/session/media_session_impl.h"
 #include "content/browser/media/session/pepper_player_delegate.h"
@@ skipping 47 matching lines @@
 
   if (players_map_.count(pp_instance))
     return;
 
   players_map_[pp_instance].reset(new PepperPlayerDelegate(
       contents_, pp_instance));
 
   MediaSessionImpl::Get(contents_)->AddPlayer(
       players_map_[pp_instance].get(), PepperPlayerDelegate::kPlayerId,
       ShouldDuckFlash() ? media::MediaContentType::Pepper
-                        : media::MediaContentType::Persistent);
+                        : media::MediaContentType::OneShot);
 }
 
 void PepperPlaybackObserver::PepperStopsPlayback(int32_t pp_instance) {
   if (!players_map_.count(pp_instance))
     return;
 
   MediaSessionImpl::Get(contents_)->RemovePlayer(
       players_map_[pp_instance].get(), PepperPlayerDelegate::kPlayerId);
 
   players_map_.erase(pp_instance);
 }
 
 }  // namespace content