Let Flash join and be controlled by media session

content/browser/media/session/pepper_playback_observer.h

Index: content/browser/media/session/pepper_playback_observer.h
diff --git a/content/browser/media/session/pepper_playback_observer.h b/content/browser/media/session/pepper_playback_observer.h
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+++ b/content/browser/media/session/pepper_playback_observer.h
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+// 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 <stdint.h>
+#include <map>
+#include <memory>
+
+#include "base/macros.h"
+
+namespace content {
+
+class PepperPlayerDelegate;
+class WebContentsImpl;
+
+// 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(WebContentsImpl* 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 =
+      std::map<int32_t, std::unique_ptr<PepperPlayerDelegate>>;
+  PlayersMap players_map_;
+
+  // Weak reference to WebContents.
+  WebContentsImpl* contents_;
+
+  DISALLOW_COPY_AND_ASSIGN(PepperPlaybackObserver);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_SESSION_PEPPER_PLAYBACK_OBSERVER_H_