Show Media Router toolbar icon ephemerally for MR dialogs

chrome/browser/ui/webui/media_router/media_router_dialog_controller_impl.h

 // Copyright 2015 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 CHROME_BROWSER_UI_WEBUI_MEDIA_ROUTER_MEDIA_ROUTER_DIALOG_CONTROLLER_IMPL_H_
 #define CHROME_BROWSER_UI_WEBUI_MEDIA_ROUTER_MEDIA_ROUTER_DIALOG_CONTROLLER_IMPL_H_
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "chrome/browser/media/router/media_router_dialog_controller.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 FORWARD_DECLARE_TEST(MediaRouterActionUnitTest, IconPressedState);
 
 class MediaRouterAction;
+class MediaRouterActionController;
 
 namespace media_router {
 
 // A desktop implementation of MediaRouterDialogController.
 // This class is not thread safe and must be called on the UI thread.
 class MediaRouterDialogControllerImpl :
     public content::WebContentsUserData<MediaRouterDialogControllerImpl>,
     public MediaRouterDialogController {
  public:
   ~MediaRouterDialogControllerImpl() override;
@@ skipping 40 matching lines @@
 
   // |action_| refers to the MediaRouterAction on the toolbar, rather than
   // overflow menu. A MediaRouterAction is always created for the toolbar
   // first. Any subsequent creations for the overflow menu will not be set as
   // |action_|.
   // The lifetime of |action_| is dependent on the creation and destruction of
   // a browser window. The overflow menu's MediaRouterAction is only created
   // when the overflow menu is opened and destroyed when the menu is closed.
   base::WeakPtr<MediaRouterAction> action_;
 
+  // |action_controller_| is responsible for showing and hiding the toolbar
+  // action. It's owned by MediaRouterUIService, which outlives |this|.
+  MediaRouterActionController* action_controller_;
+
   base::WeakPtrFactory<MediaRouterDialogControllerImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaRouterDialogControllerImpl);
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_UI_WEBUI_MEDIA_ROUTER_MEDIA_ROUTER_DIALOG_CONTROLLER_IMPL_H_