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

chrome/browser/media/media_internals.h

Index: chrome/browser/media/media_internals.h
===================================================================
--- chrome/browser/media/media_internals.h	(revision 128803)
+++ chrome/browser/media/media_internals.h	(working copy)
@@ -7,8 +7,8 @@
 #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"
 
@@ -19,12 +19,14 @@
 }
 
 // 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,
@@ -47,8 +49,8 @@
   void SendEverything();
 
  private:
-  friend class IOThread;
   friend class MediaInternalsTest;
+  friend struct DefaultSingletonTraits<MediaInternals>;
 
   MediaInternals();