Link MediaSessionTabHelper with native MediaSession [CL is going to be split]

content/browser/web_contents/web_contents_impl.h

Index: content/browser/web_contents/web_contents_impl.h
diff --git a/content/browser/web_contents/web_contents_impl.h b/content/browser/web_contents/web_contents_impl.h
index 000a9316e71c54b5e5392441ff6a4041ccc64586..aa9fa20f48fd6882c8258f5af19f2dc25c571e08 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -413,9 +413,6 @@ class CONTENT_EXPORT WebContentsImpl
   void GetManifest(const GetManifestCallback& callback) override;
   void ExitFullscreen(bool will_cause_resize) override;
   void ResumeLoadingCreatedWebContents() override;
-  void ResumeMediaSession() override;
-  void SuspendMediaSession() override;
-  void StopMediaSession() override;
   void OnPasswordInputShownOnHttp() override;
   void OnCreditCardInputShownOnHttp() override;
 
@@ -430,13 +427,6 @@ class CONTENT_EXPORT WebContentsImpl
   bool GetAllowOtherViews() override;
 #endif
 
-  // This method is called when the MediaSession state has changed, and will
-  // notify the WebContents observers.
-  void OnMediaSessionStateChanged();
-  // This method is called when the MediaSession metadata has changed, and will
-  // notify the WebContents observers.
-  void OnMediaSessionMetadataChanged();
-
   // Implementation of PageNavigator.
   WebContents* OpenURL(const OpenURLParams& params) override;