Let Flash join and be controlled by media session

content/browser/media/session/pepper_web_contents_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_WEB_CONTENTS_OBSERVER_H_
+#define CONTENT_BROWSER_MEDIA_SESSION_PEPPER_WEB_CONTENTS_OBSERVER_H_
+
+#include "content/public/browser/web_contents_observer.h"
+
+#include <map>
+#include <memory>
+#include <set>
+
+namespace content {
+
+class PepperPlayerDelegate;
+class MediaSession;
+
+class PepperWebContentsObserver : public WebContentsObserver {
+ public:
+  explicit PepperWebContentsObserver(WebContents* web_contents);
+  ~PepperWebContentsObserver() override;
+
+  void WebContentsDestroyed() override;

[jochen (gone - plz use gerrit), 2016/06/27 11:47:11]

// WebContentsObserver implementation.

[Zhiqiang Zhang (Slow), 2016/06/28 18:53:24]

Done.

+  void PepperInstanceCreated(int32_t pp_instance) override;
+  void PepperInstanceDeleted(int32_t pp_instance) override;
+
+  bool OnMessageReceived(const IPC::Message& msg,
+                         RenderFrameHost* render_frame_host) override;
+  void OnPepperStartsPlayback(int32_t pp_instance);

[jochen (gone - plz use gerrit), 2016/06/27 11:47:11]

this is no longer WCO, please move to a separate block 

[Zhiqiang Zhang (Slow), 2016/06/28 18:53:24]

Done.

+  void OnPepperStopsPlayback(int32_t pp_instance);
+
+ private:
+
+  using PlayersMap =
+      std::map<int32_t, std::unique_ptr<PepperPlayerDelegate>>;

[jochen (gone - plz use gerrit), 2016/06/27 11:47:11]

base::IdMap?

[Zhiqiang Zhang (Slow), 2016/06/28 18:53:24]

Done.

+  PlayersMap players_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(PepperWebContentsObserver);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_SESSION_PEPPER_WEB_CONTENTS_OBSERVER_H_