[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 722745255b949eb1d22bd56fda177439e377fe63..799691ef0504266ed3904d9c915a2478e7480b87 100644
--- a/chrome/browser/ui/toolbar/media_router_action_controller.cc
+++ b/chrome/browser/ui/toolbar/media_router_action_controller.cc
@@ -18,7 +18,6 @@ MediaRouterActionController::MediaRouterActionController(Profile* profile)
           ToolbarActionsModel::Get(profile)->component_migration_helper()) {}
 
 MediaRouterActionController::~MediaRouterActionController() {
-  UnregisterObserver();  // media_router::IssuesObserver.
 }
 
 void MediaRouterActionController::OnIssueUpdated(
@@ -52,7 +51,7 @@ MediaRouterActionController::MediaRouterActionController(
       component_migration_helper_(component_migration_helper) {
   DCHECK(profile_);
   DCHECK(component_action_delegate_);
-  RegisterObserver();  // media_router::IssuesObserver.
+  media_router::IssuesObserver::Init();
   pref_change_registrar_.Init(profile->GetPrefs());
   pref_change_registrar_.Add(
       prefs::kToolbarMigratedComponentActionStatus,