Move the MediaObserver getter from ResourceContext to ContentBrowserClient, since we only need to s…

chrome/browser/media/media_internals.h

 // Copyright (c) 2012 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 CHROME_BROWSER_MEDIA_MEDIA_INTERNALS_H_
 #define CHROME_BROWSER_MEDIA_MEDIA_INTERNALS_H_
 #pragma once
 
 #include "base/memory/ref_counted.h"
+#include "base/memory/singleton.h"
 #include "base/observer_list.h"
-#include "base/threading/non_thread_safe.h"
 #include "base/values.h"
 #include "content/public/browser/media_observer.h"
 
 class MediaInternalsObserver;
 
 namespace media {
 struct MediaLogEvent;
 }
 
 // This class stores information about currently active media.
-// All of its methods are called on the IO thread.
-class MediaInternals : public content::MediaObserver,
-                       public base::NonThreadSafe {
+// It's constructed on the UI thread but all of its methods are called on the IO
+// thread.
+class MediaInternals : public content::MediaObserver {
  public:
   virtual ~MediaInternals();
 
+  static MediaInternals* GetInstance();
+
   // Overridden from content::MediaObserver:
   virtual void OnDeleteAudioStream(void* host, int stream_id) OVERRIDE;
   virtual void OnSetAudioStreamPlaying(void* host,
                                        int stream_id,
                                        bool playing) OVERRIDE;
   virtual void OnSetAudioStreamStatus(void* host,
                                       int stream_id,
                                       const std::string& status) OVERRIDE;
   virtual void OnSetAudioStreamVolume(void* host,
                                       int stream_id,
                                       double volume) OVERRIDE;
   virtual void OnMediaEvent(int render_process_id,
                             const media::MediaLogEvent& event) OVERRIDE;
 
   // Methods for observers.
   // Observers should add themselves on construction and remove themselves
   // on destruction.
   void AddObserver(MediaInternalsObserver* observer);
   void RemoveObserver(MediaInternalsObserver* observer);
   void SendEverything();
 
  private:
-  friend class IOThread;
   friend class MediaInternalsTest;
+  friend struct DefaultSingletonTraits<MediaInternals>;
 
   MediaInternals();
 
   // Sets |property| of an audio stream to |value| and notifies observers.
   // (host, stream_id) is a unique id for the audio stream.
   // |host| will never be dereferenced.
   void UpdateAudioStream(void* host, int stream_id,
                          const std::string& property, Value* value);
 
   // Removes |item| from |data_|.
   void DeleteItem(const std::string& item);
 
   // Sets data_.id.property = value and notifies attached UIs using update_fn.
   // id may be any depth, e.g. "video.decoders.1.2.3"
   void UpdateItem(const std::string& update_fn, const std::string& id,
                   const std::string& property, Value* value);
 
   // Calls javascript |function|(|value|) on each attached UI.
   void SendUpdate(const std::string& function, Value* value);
 
   static MediaInternals* instance_;
   DictionaryValue data_;
   ObserverList<MediaInternalsObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaInternals);
 };
 
 #endif  // CHROME_BROWSER_MEDIA_MEDIA_INTERNALS_H_