Fix two notification update issues on page navigation

content/browser/media/session/media_session_service_impl.h

 // Copyright 2016 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_BROWSER_MEDIA_SESSION_MEDIA_SESSION_SERVICE_IMPL_H_
 #define CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_SERVICE_IMPL_H_
 
 #include "base/optional.h"
 #include "content/public/common/media_metadata.h"
 #include "mojo/public/cpp/bindings/binding.h"
@@ skipping 18 matching lines @@
   RenderFrameHost* GetRenderFrameHost();
 
   blink::mojom::MediaSessionPlaybackState playback_state() const {
     return playback_state_;
   }
   const base::Optional<MediaMetadata>& metadata() const { return metadata_; }
   const std::set<blink::mojom::MediaSessionAction>& actions() const {
     return actions_;
   }
 
+  void Reset();
+
   // blink::mojom::MediaSessionService implementation.
   void SetClient(blink::mojom::MediaSessionClientPtr client) override;
 
   void SetPlaybackState(blink::mojom::MediaSessionPlaybackState state) override;
   void SetMetadata(const base::Optional<MediaMetadata>& metadata) override;
 
   void EnableAction(blink::mojom::MediaSessionAction action) override;
   void DisableAction(blink::mojom::MediaSessionAction action) override;
 
  protected:
@@ skipping 14 matching lines @@
   blink::mojom::MediaSessionPlaybackState playback_state_;
   base::Optional<MediaMetadata> metadata_;
   std::set<blink::mojom::MediaSessionAction> actions_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaSessionServiceImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_SESSION_MEDIA_SESSION_SERVICE_IMPL_H_