Show Media Router toolbar icon ephemerally for MR dialogs

chrome/browser/ui/toolbar/media_router_action_controller.h

Index: chrome/browser/ui/toolbar/media_router_action_controller.h
diff --git a/chrome/browser/ui/toolbar/media_router_action_controller.h b/chrome/browser/ui/toolbar/media_router_action_controller.h
index 9965f6b3c2e04380e4c762a919d5934457aad0dd..d2bfda782ce451d7fe60a21c9abe0a6fba2e1abd 100644
--- a/chrome/browser/ui/toolbar/media_router_action_controller.h
+++ b/chrome/browser/ui/toolbar/media_router_action_controller.h
@@ -22,6 +22,13 @@ class MediaRouterActionController : public media_router::IssuesObserver,
                                     public media_router::MediaRoutesObserver {
  public:
   explicit MediaRouterActionController(Profile* profile);
+  // Constructor for injecting dependencies in tests.
+  MediaRouterActionController(
+      Profile* profile,
+      media_router::MediaRouter* router,
+      ComponentMigrationHelper::ComponentActionDelegate*
+          component_action_delegate,
+      ComponentMigrationHelper* component_migration_helper);
   ~MediaRouterActionController() override;
 
   // media_router::IssuesObserver:
@@ -32,22 +39,22 @@ class MediaRouterActionController : public media_router::IssuesObserver,
                        const std::vector<media_router::MediaRoute::Id>&
                            joinable_route_ids) override;
 
+  // Called when a Media Router dialog is shown or hidden, and updates the
+  // visibility of the action icon. Overridden in tests.
+  virtual void OnDialogShown();
+  virtual void OnDialogHidden();
+
  private:
   friend class MediaRouterActionControllerUnitTest;
-  FRIEND_TEST_ALL_PREFIXES(MediaRouterActionControllerUnitTest, EphemeralIcon);
-
-  // Constructor for injecting dependencies in tests.
-  MediaRouterActionController(
-      Profile* profile,
-      media_router::MediaRouter* router,
-      ComponentMigrationHelper::ComponentActionDelegate*
-          component_action_delegate,
-      ComponentMigrationHelper* component_migration_helper);
+  FRIEND_TEST_ALL_PREFIXES(MediaRouterActionControllerUnitTest,
+                           EphemeralIconForRoutesAndIssues);
+  FRIEND_TEST_ALL_PREFIXES(MediaRouterActionControllerUnitTest,
+                           EphemeralIconForDialog);
 
   // Adds or removes the Media Router action icon to/from
   // |component_action_delegate_| if necessary, depending on whether or not
-  // we have issues or local routes.
-  void MaybeAddOrRemoveAction();
+  // we have issues, local routes or a dialog.
+  virtual void MaybeAddOrRemoveAction();
 
   // Returns |true| if the Media Router action should be present on the toolbar
   // or the overflow menu.
@@ -69,6 +76,9 @@ class MediaRouterActionController : public media_router::IssuesObserver,
   bool has_issue_ = false;
   bool has_local_display_route_ = false;
 
+  // The number of dialogs that are currently open.
+  size_t dialog_count_ = 0;
+
   PrefChangeRegistrar pref_change_registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaRouterActionController);