Let Flash join and be controlled by media session

content/browser/media/session/pepper_playback_observer.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_PEPPER_PLAYBACK_OBSERVER_H_
+#define CONTENT_BROWSER_MEDIA_SESSION_PEPPER_PLAYBACK_OBSERVER_H_
+
+#include "base/id_map.h"
+#include "content/public/browser/web_contents_observer.h"
+
+namespace content {
+
+class PepperPlayerDelegate;
+
+// Class observing Pepper playback changes from WebContents, and update
+// MediaSession accordingly. Can only be a member of WebContentsImpl and must be
+// destroyed in ~WebContentsImpl().
+class PepperPlaybackObserver {
+ public:
+  explicit PepperPlaybackObserver(WebContents* contents);
+  virtual ~PepperPlaybackObserver();
+
+  void PepperInstanceCreated(int32_t pp_instance);
+  void PepperInstanceDeleted(int32_t pp_instance);
+  void PepperStartsPlayback(int32_t pp_instance);
+  void PepperStopsPlayback(int32_t pp_instance);
+
+ private:
+  // Owning PepperPlayerDelegates.
+  using PlayersMap =
+      IDMap<PepperPlayerDelegate, IDMapOwnPointer, int32_t>;
+  PlayersMap players_map_;
+
+  // Weak reference to WebContents.
+  WebContents* contents_;

[dcheng, 2016/06/30 07:02:39]

Nit: suggest just making this a WebContentsImpl, to avoid the static_casts in
the .cc

[Zhiqiang Zhang (Slow), 2016/06/30 12:46:54]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(PepperPlaybackObserver);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_SESSION_PEPPER_PLAYBACK_OBSERVER_H_