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 3afb1aab039d99d206c9b33af0d666dbd9d6c669..172ec8ba30be77a1d30a1ff52bbc0ad7483443e5 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -412,9 +412,6 @@ 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;
 
@@ -429,13 +426,6 @@ 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;