mash: Change the MediaDelegate to a Media{Controller,Client}.

chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h

Index: chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h
diff --git a/chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h b/chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h
index f3faec78ce48c1fd8669267feb129cc40d69cecb..6d50ed29f109726d5c4f31ede20d837701636265 100644
--- a/chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h
+++ b/chrome/browser/ui/views/ash/chrome_browser_main_extra_parts_ash.h
@@ -15,6 +15,7 @@ class ChromeLauncherControllerMus;
 class ChromeNewWindowClient;
 class ImmersiveContextMus;
 class ImmersiveHandlerFactoryMus;
+class MediaClient;
 class SessionControllerClient;
 class SystemTrayClient;
 class VolumeController;
@@ -33,6 +34,7 @@ class ChromeBrowserMainExtraPartsAsh : public ChromeBrowserMainExtraParts {
  private:
   std::unique_ptr<ChromeLauncherControllerMus> chrome_launcher_controller_mus_;
   std::unique_ptr<CastConfigClientMediaRouter> cast_config_client_media_router_;
+  std::unique_ptr<MediaClient> media_client_;
   std::unique_ptr<ImmersiveHandlerFactoryMus> immersive_handler_factory_;
   std::unique_ptr<ImmersiveContextMus> immersive_context_;
   std::unique_ptr<SessionControllerClient> session_controller_client_;