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

content/public/browser/web_contents_observer.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 CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
@@ skipping 20 matching lines @@
 class RenderFrameHost;
 class RenderViewHost;
 class RenderWidgetHost;
 class WebContents;
 class WebContentsImpl;
 struct AXEventNotificationDetails;
 struct AXLocationChangeNotificationDetails;
 struct FaviconURL;
 struct FrameNavigateParams;
 struct LoadCommittedDetails;
-struct MediaMetadata;
 struct Referrer;
 struct ResourceRedirectDetails;
 struct ResourceRequestDetails;
 struct SecurityStyleExplanations;
 
 // An observer API implemented by classes which are interested in various page
 // load events from WebContents.  They also get a chance to filter IPC messages.
 //
 // Since a WebContents can be a delegate to almost arbitrarily many
 // RenderViewHosts, it is important to check in those WebContentsObserver
@@ skipping 409 matching lines @@
 
   // Invoked when media is playing or paused.  |id| is unique per player and per
   // RenderFrameHost.  There may be multiple players within a RenderFrameHost
   // and subsequently within a WebContents.  MediaStartedPlaying() will always
   // be followed by MediaStoppedPlaying() after player teardown.  Observers must
   // release all stored copies of |id| when MediaStoppedPlaying() is received.
   using MediaPlayerId = std::pair<RenderFrameHost*, int>;
   virtual void MediaStartedPlaying(const MediaPlayerId& id) {}
   virtual void MediaStoppedPlaying(const MediaPlayerId& id) {}
 
-  // Invoked when media session has changed its state.
-  virtual void MediaSessionStateChanged(bool is_controllable,
-                                        bool is_suspended) {}
-
-  // Invoked when media session metadata has changed. When |metadata| is
-  // nullopt, it means the metadata is being unset.
-  virtual void MediaSessionMetadataChanged(
-      const base::Optional<MediaMetadata>& metadata) {}
-
   // Invoked when the renderer process changes the page scale factor.
   virtual void OnPageScaleFactorChanged(float page_scale_factor) {}
 
   // Invoked if an IPC message is coming from a specific RenderFrameHost.
   virtual bool OnMessageReceived(const IPC::Message& message,
                                  RenderFrameHost* render_frame_host);
 
   // Notification that |contents| has gained focus.
   virtual void OnWebContentsFocused() {}
 
@@ skipping 27 matching lines @@
   void ResetWebContents();
 
   WebContentsImpl* web_contents_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_