[Media>Session] Pause all players for non-routed frames when receiving PAUSE action

content/browser/media/session/media_session_impl.cc

 // Copyright 2015 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/media_session_impl.h"
 
 #include <algorithm>
 #include "content/browser/media/session/audio_focus_delegate.h"
 #include "content/browser/media/session/media_session_controller.h"
 #include "content/browser/media/session/media_session_player_observer.h"
@@ skipping 593 matching lines @@
 void MediaSessionImpl::OnMediaSessionActionsChanged(
     MediaSessionServiceImpl* service) {
   if (service != routed_service_)
     return;
 
   NotifyMediaSessionActionsChange(routed_service_->actions());
 }
 
 void MediaSessionImpl::DidReceiveAction(
     blink::mojom::MediaSessionAction action) {
+  // Pause all players in non-routed frames if the action is PAUSE.
+  //
+  // This is the default PAUSE action handler per Media Session API spec. The
+  // reason for pausing all players in all other sessions is to avoid the
+  // players in other frames keep the session active so that the UI will always
+  // show the pause button but it does not pause anything (as the routed frame
+  // already pauses when responding to the PAUSE action while other frames does
+  // not).
+  //
+  // TODO(zqzhang): Currently, this might not work well on desktop as Pepper and
+  // OneShot players are not really suspended, so that the session is still
+  // active after this. See https://crbug.com/619084 and
+  // https://crbug.com/596516.
+  if (blink::mojom::MediaSessionAction::PAUSE == action) {
+    RenderFrameHost* rfh_of_routed_service =
+        routed_service_->GetRenderFrameHost();
+    for (const auto& player : normal_players_) {
+      if (player.observer->GetRenderFrameHost() != rfh_of_routed_service)
+        player.observer->OnSuspend(player.player_id);
+    }
+    for (const auto& player : pepper_players_) {
+      if (player.observer->GetRenderFrameHost() != rfh_of_routed_service) {
+        player.observer->OnSetVolumeMultiplier(player.player_id,
+                                               kDuckingVolumeMultiplier);
+      }
+    }
+    for (const auto& player : one_shot_players_) {
+      if (player.observer->GetRenderFrameHost() != rfh_of_routed_service)
+        player.observer->OnSuspend(player.player_id);
+    }
+  }
+
   if (!routed_service_)
     return;
 
   routed_service_->GetClient()->DidReceiveAction(action);
 }
 
 bool MediaSessionImpl::IsServiceActiveForRenderFrameHost(RenderFrameHost* rfh) {
   return services_.find(rfh) != services_.end();
 }
 
@@ skipping 44 matching lines @@
     if (!IsServiceActiveForRenderFrameHost(frame))
       continue;
     best_frame = frame;
     min_depth = depth;
   }
 
   return best_frame ? services_[best_frame] : nullptr;
 }
 
 }  // namespace content