Allow MediaSession in iframes to be routed

content/browser/media/session/media_session_service_router.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_SESSION_SERVICE_ROUTER_H_
+#define CONTENT_BROWSER_MEDIA_SESSION_SERVICE_ROUTER_H_
+
+#include <map>
+
+#include "base/macros.h"
+
+namespace blink {
+namespace mojom {
+enum class MediaSessionAction;
+}  // namespace mojom
+}  // namespace blink;
+
+namespace content {
+
+class MediaSessionImpl;
+class MediaSessionServiceImpl;
+class RenderFrameHost;
+
+class MediaSessionServiceRouter final {
+ public:
+  MediaSessionServiceRouter(MediaSessionImpl* session);
+  ~MediaSessionServiceRouter();
+
+  void OnServiceCreated(MediaSessionServiceImpl* service);

[whywhat, 2016/11/22 23:13:16]

nit: document public methods and the class.

[Zhiqiang Zhang (Slow), 2016/11/25 14:50:41]

Done.

+  void OnServiceDestroyed(MediaSessionServiceImpl* service);
+
+  void OnMediaSessionMetadataChanged(MediaSessionServiceImpl* service);
+  void OnMediaSessionActionsChanged(MediaSessionServiceImpl* service);
+
+  void DidReceiveAction(blink::mojom::MediaSessionAction action);
+
+  void MostMeaningfulPlayerObserverMayHaveChanged();
+
+ private:
+  void UpdateRoutedService(MediaSessionServiceImpl* service);
+  bool IsServiceActiveForRenderFrameHost(RenderFrameHost* rfh);
+
+  using ServicesMap = std::map<RenderFrameHost*, MediaSessionServiceImpl*>;
+
+  ServicesMap services_;
+  MediaSessionServiceImpl* routed_service_;

[whywhat, 2016/11/22 23:13:16]

What's the life scope of these pointers? session_ owns the router so keeping a
pointer is probably safe, what about the service?

[Zhiqiang Zhang (Slow), 2016/11/25 14:50:41]

Documented on the ownership.

+  MediaSessionImpl* session_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaSessionServiceRouter);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_SESSION_SERVICE_ROUTER_H_