Show the Cast toolbar icon ephemerally when Cast is in use

chrome/browser/extensions/component_migration_helper.cc

 // 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.
 
 #include "chrome/browser/extensions/component_migration_helper.h"
 
 #include "base/stl_util.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_system_impl.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/toolbar/component_toolbar_actions_factory.h"
 #include "chrome/common/pref_names.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
 #include "components/prefs/scoped_user_pref_update.h"
 #include "content/public/browser/browser_context.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/common/feature_switch.h"
 
 namespace extensions {
 
@@ skipping 105 matching lines @@
     const Extension* extension) {
   const ExtensionId& extension_id = extension->id();
   const std::string& component_action_id =
       GetActionIdForExtensionId(extension_id);
   if (component_action_id.empty())
     return;
   if (ContainsKey(enabled_actions_, component_action_id)) {
     UnloadExtension(extension_id);
     SetComponentActionPref(component_action_id, true);
 
+    if (component_action_id ==
+        ComponentToolbarActionsFactory::kMediaRouterActionId) {
+      pref_service_->SetBoolean(prefs::kMediaRouterAlwaysShowActionIcon,
+                                true);
+    }
+
     if (!delegate_->HasComponentAction(component_action_id))
       delegate_->AddComponentAction(component_action_id);
   }
 }
 
 void ComponentMigrationHelper::SetComponentActionPref(
     const std::string& component_action_id,
     bool enabled) {
   DictionaryPrefUpdate update(pref_service_,
                               ::prefs::kToolbarMigratedComponentActionStatus);
@@ skipping 32 matching lines @@
 std::string ComponentMigrationHelper::GetActionIdForExtensionId(
     const ExtensionId& extension_id) const {
   for (const auto& i : migrated_actions_) {
     if (i.second == extension_id)
       return i.first;
   }
   return "";
 }
 
 }  // namespace extensions