Let Flash take one-shot focus in default MediaSession

content/browser/media/session/pepper_player_delegate.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_player_delegate.h"
 
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/browser/media/session/pepper_playback_observer.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/frame_messages.h"
+#include "media/base/media_switches.h"
 
 namespace content {
 
 namespace {
 
 const double kDuckVolume = 0.2f;
 
+bool ShouldDuckFlash() {
+  return base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+             switches::kEnableDefaultMediaSession) ==
+         switches::kEnableDefaultMediaSessionDuckFlash;
+}
+
 }  // anonymous namespace
 
 const int PepperPlayerDelegate::kPlayerId = 0;
 
 PepperPlayerDelegate::PepperPlayerDelegate(
     WebContentsImpl* contents, int32_t pp_instance)
     : contents_(contents),
       pp_instance_(pp_instance) {}
 
 PepperPlayerDelegate::~PepperPlayerDelegate() = default;
 
 void PepperPlayerDelegate::OnSuspend(int player_id) {
+  if (!ShouldDuckFlash())
+    return;
+
   // Pepper player cannot be really suspended. Duck the volume instead.
   DCHECK_EQ(player_id, kPlayerId);
   SetVolume(player_id, kDuckVolume);
 }
 
 void PepperPlayerDelegate::OnResume(int player_id) {
+  if (!ShouldDuckFlash())
+    return;
+
   DCHECK_EQ(player_id, kPlayerId);
   SetVolume(player_id, 1.0f);
 }
 
 void PepperPlayerDelegate::OnSetVolumeMultiplier(int player_id,
                                                  double volume_multiplier) {
+  if (!ShouldDuckFlash())
+    return;
+
   DCHECK_EQ(player_id, kPlayerId);
   SetVolume(player_id, volume_multiplier);
 }
 
 void PepperPlayerDelegate::SetVolume(int player_id, double volume) {
   contents_->Send(new FrameMsg_SetPepperVolume(
       contents_->GetMainFrame()->routing_id(), pp_instance_, volume));
 }
 
 }  // namespace content