Show the Cast toolbar icon ephemerally when Cast is in use

chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc

Index: chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc
diff --git a/chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc b/chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc
index 487a59a88d9ba57f538fb13f71c930c0a21db8ee..c9b2081749b30616250b600737a92ddc3756ac07 100644
--- a/chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc
+++ b/chrome/browser/ui/toolbar/component_toolbar_actions_factory.cc
@@ -11,6 +11,7 @@
 #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)
@@ -44,6 +45,10 @@ ComponentToolbarActionsFactory* ComponentToolbarActionsFactory::GetInstance() {
 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;
 }
 
@@ -94,3 +99,7 @@ void ComponentToolbarActionsFactory::HandleComponentMigrations(
   }
 }
 
+bool ComponentToolbarActionsFactory::IsComponentActionId(
+    const std::string& id) {
+  return id == kMediaRouterActionId;
+}