Add a policy to always show the Cast toolbar icon

chrome/browser/ui/toolbar/media_router_action_controller.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 CHROME_BROWSER_UI_TOOLBAR_MEDIA_ROUTER_ACTION_CONTROLLER_H_
 #define CHROME_BROWSER_UI_TOOLBAR_MEDIA_ROUTER_ACTION_CONTROLLER_H_
 
 #include <vector>
 
 #include "chrome/browser/extensions/component_migration_helper.h"
@@ skipping 13 matching lines @@
   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;
 
+  // Whether the media router action is shown by an administrator policy.
+  static bool IsActionShownByPolicy(Profile* profile);
+
   // media_router::IssuesObserver:
   void OnIssue(const media_router::Issue& issue) override;
   void OnIssuesCleared() override;
 
   // media_router::MediaRoutesObserver:
   void OnRoutesUpdated(const std::vector<media_router::MediaRoute>& routes,
                        const std::vector<media_router::MediaRoute::Id>&
                            joinable_route_ids) override;
 
   // Called when a Media Router dialog is shown or hidden, and updates the
@@ skipping 26 matching lines @@
   ComponentMigrationHelper::ComponentActionDelegate* const
       component_action_delegate_;
 
   // Responsible for changing the pref to always show or hide component actions.
   // It is owned by ToolbarActionsModel and outlives |this|.
   ComponentMigrationHelper* const component_migration_helper_;
 
   bool has_issue_ = false;
   bool has_local_display_route_ = false;
 
+  // Whether the media router action is shown by an administrator policy.
+  bool shown_by_policy_;
+
   // The number of dialogs that are currently open.
   size_t dialog_count_ = 0;
 
   PrefChangeRegistrar pref_change_registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(MediaRouterActionController);
 };
 
 #endif  // CHROME_BROWSER_UI_TOOLBAR_MEDIA_ROUTER_ACTION_CONTROLLER_H_