[Media Router] Clean up issues related code.

chrome/browser/ui/toolbar/media_router_action_controller.cc

Index: chrome/browser/ui/toolbar/media_router_action_controller.cc
diff --git a/chrome/browser/ui/toolbar/media_router_action_controller.cc b/chrome/browser/ui/toolbar/media_router_action_controller.cc
index bc46d00cb20b96a8cddf54d9589457ef7f914065..932ea1fb15c740111499d1080bab2fcfe2575eb0 100644
--- a/chrome/browser/ui/toolbar/media_router_action_controller.cc
+++ b/chrome/browser/ui/toolbar/media_router_action_controller.cc
@@ -22,7 +22,6 @@ MediaRouterActionController::MediaRouterActionController(Profile* profile)
 
 MediaRouterActionController::~MediaRouterActionController() {
   DCHECK_EQ(dialog_count_, 0u);
-  UnregisterObserver();  // media_router::IssuesObserver.
 }
 
 void MediaRouterActionController::OnIssueUpdated(
@@ -67,7 +66,8 @@ MediaRouterActionController::MediaRouterActionController(
       component_action_delegate_(component_action_delegate),
       component_migration_helper_(component_migration_helper) {
   DCHECK(profile_);
-  RegisterObserver();  // media_router::IssuesObserver.
+  DCHECK(component_action_delegate_);
+  media_router::IssuesObserver::Init();
   pref_change_registrar_.Init(profile->GetPrefs());
   pref_change_registrar_.Add(
       prefs::kToolbarMigratedComponentActionStatus,