arc: Rename methods in ArcSessionManager::Observer.

chrome/browser/ui/ash/launcher/arc_app_deferred_launcher_controller.cc

Index: chrome/browser/ui/ash/launcher/arc_app_deferred_launcher_controller.cc
diff --git a/chrome/browser/ui/ash/launcher/arc_app_deferred_launcher_controller.cc b/chrome/browser/ui/ash/launcher/arc_app_deferred_launcher_controller.cc
index 459433c5fb40927967d980fc639dbfd622cecb2c..3496b567aa9bcaff249735dced6c0d0991362a2f 100644
--- a/chrome/browser/ui/ash/launcher/arc_app_deferred_launcher_controller.cc
+++ b/chrome/browser/ui/ash/launcher/arc_app_deferred_launcher_controller.cc
@@ -140,7 +140,7 @@ void ArcAppDeferredLauncherController::OnAppRemoved(const std::string& app_id) {
   Close(app_id);
 }
 
-void ArcAppDeferredLauncherController::OnOptInEnabled(bool enabled) {
+void ArcAppDeferredLauncherController::OnArcOptInChanged(bool enabled) {
   if (enabled)
     return;