Let Flash join and be controlled by media session

content/browser/media/pepper/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_RENDER_PEPPER_PEPPER_WEB_CONTENTS_OBSERVER_H_
+#define CONTENT_RENDER_PEPPER_PEPPER_WEB_CONTENTS_OBSERVER_H_
+
+#include "content/public/browser/web_contents_observer.h"
+
+#include <map>
+#include <memory>
+
+namespace content {
+class PepperPlayerDelegate;

[mlamouri (slow - plz ping), 2016/06/23 13:23:20]

style: leave empty line above.

[Zhiqiang Zhang (Slow), 2016/06/24 17:43:20]

Done.

+class MediaSession;
+
+class CONTENT_EXPORT PepperWebContentsObserver : public WebContentsObserver {

[mlamouri (slow - plz ping), 2016/06/23 13:23:20]

Why CONTENT_EXPORT?

[Zhiqiang Zhang (Slow), 2016/06/24 17:43:20]

Removed.

+ public:
+  explicit PepperWebContentsObserver(WebContents* web_contents);
+  ~PepperWebContentsObserver() override;
+
+  void WebContentsDestroyed() override;
+  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);
+  void OnPepperStopsPlayback(int32_t pp_instance);
+
+ private:
+
+  using PlayersMap =
+      std::map<int32_t, std::unique_ptr<PepperPlayerDelegate>>;
+  PlayersMap players_map_;
+  MediaSession* media_session_;

[mlamouri (slow - plz ping), 2016/06/23 13:23:20]

FWIW, I don't think you need this. You could as well call
`MediaSession::Get(web_contents)` when needed.

[Zhiqiang Zhang (Slow), 2016/06/24 17:43:21]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(PepperWebContentsObserver);
+};
+}

[mlamouri (slow - plz ping), 2016/06/23 13:23:20]

style: add empty line above and "  // namespace content"

[Zhiqiang Zhang (Slow), 2016/06/24 17:43:21]

Done.

+
+#endif  // CONTENT_RENDER_PEPPER_PEPPER_WEB_CONTENTS_OBSERVER_H_