Show the Cast toolbar icon ephemerally when Cast is in use

chrome/browser/ui/toolbar/media_router_contextual_menu.h

Index: chrome/browser/ui/toolbar/media_router_contextual_menu.h
diff --git a/chrome/browser/ui/toolbar/media_router_contextual_menu.h b/chrome/browser/ui/toolbar/media_router_contextual_menu.h
index 234f7852597e4be46c1ef75b09ec94a17e130c61..4e5ef64755023dcba11de2d213174d7a92a9ed13 100644
--- a/chrome/browser/ui/toolbar/media_router_contextual_menu.h
+++ b/chrome/browser/ui/toolbar/media_router_contextual_menu.h
@@ -10,6 +10,7 @@
 #include "ui/base/models/simple_menu_model.h"
 
 class Browser;
+class MediaRouterAction;
 
 // The class for the contextual menu for the Media Router action.
 class MediaRouterContextualMenu : public ui::SimpleMenuModel::Delegate {
@@ -18,6 +19,7 @@ class MediaRouterContextualMenu : public ui::SimpleMenuModel::Delegate {
   ~MediaRouterContextualMenu() override;
 
   ui::MenuModel* menu_model() { return &menu_model_; }
+  void SetMediaRouterAction(MediaRouterAction* action);
 
  private:
   // ui::SimpleMenuModel::Delegate:
@@ -27,10 +29,10 @@ class MediaRouterContextualMenu : public ui::SimpleMenuModel::Delegate {
   void ExecuteCommand(int command_id, int event_flags) override;
 
   void ReportIssue();
-  void RemoveMediaRouterComponentAction();
 
   Browser* browser_;
   ui::SimpleMenuModel menu_model_;
+  MediaRouterAction* action_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaRouterContextualMenu);
 };