Show the Cast toolbar icon ephemerally when Cast is in use

chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc

 // Copyright 2014 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.
 
 #include "chrome/browser/ui/toolbar/component_toolbar_actions_factory.h"
 
 #include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "chrome/browser/extensions/component_migration_helper.h"
 #include "chrome/browser/media/router/media_router_feature.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/toolbar/toolbar_action_view_controller.h"
+#include "chrome/common/pref_names.h"
 #include "extensions/common/feature_switch.h"
 
 #if defined(ENABLE_MEDIA_ROUTER)
 #include "chrome/browser/ui/toolbar/media_router_action.h"
 #endif
 
 namespace {
 
 ComponentToolbarActionsFactory* testing_factory_ = nullptr;
 
@@ skipping 13 matching lines @@
 ComponentToolbarActionsFactory::~ComponentToolbarActionsFactory() {}
 
 // static
 ComponentToolbarActionsFactory* ComponentToolbarActionsFactory::GetInstance() {
   return testing_factory_ ? testing_factory_ : &lazy_factory.Get();
 }
 
 std::set<std::string> ComponentToolbarActionsFactory::GetInitialComponentIds(
     Profile* profile) {
   std::set<std::string> component_ids;
+#if defined(ENABLE_MEDIA_ROUTER)
+  if (profile->GetPrefs()->GetBoolean(prefs::kMediaRouterAlwaysShowActionIcon))
+    component_ids.insert(kMediaRouterActionId);
+#endif  // defined(ENABLE_MEDIA_ROUTER)
   return component_ids;
 }
 
 std::unique_ptr<ToolbarActionViewController>
 ComponentToolbarActionsFactory::GetComponentToolbarActionForId(
     const std::string& id,
     Browser* browser,
     ToolbarActionsBar* bar) {
   // This is currently behind the extension-action-redesign flag, as it is
   // designed for the new toolbar.
@@ skipping 29 matching lines @@
 
 void ComponentToolbarActionsFactory::HandleComponentMigrations(
     extensions::ComponentMigrationHelper* helper,
     Profile* profile) const {
   if (media_router::MediaRouterEnabled(profile)) {
     helper->OnFeatureEnabled(kMediaRouterActionId);
   } else {
     helper->OnFeatureDisabled(kMediaRouterActionId);
   }
 }
-