[cros] check for updates in WebUI OOBE can be cancelled in dev builds.

chrome/browser/chromeos/login/update_screen.cc

Index: chrome/browser/chromeos/login/update_screen.cc
diff --git a/chrome/browser/chromeos/login/update_screen.cc b/chrome/browser/chromeos/login/update_screen.cc
index f1dc23c3ea4ba72de467beb881409cc939aec13c..8e70834adde957e927f5cd3d4ba56b07f64b3e33 100644
--- a/chrome/browser/chromeos/login/update_screen.cc
+++ b/chrome/browser/chromeos/login/update_screen.cc
@@ -77,12 +77,15 @@ UpdateScreen::UpdateScreen(ScreenObserver* screen_observer,
       is_shown_(false),
       ignore_idle_status_(true),
       actor_(actor) {
+  actor_->SetDelegate(this);
   GetInstanceSet().insert(this);
 }
 
 UpdateScreen::~UpdateScreen() {
   CrosLibrary::Get()->GetUpdateLibrary()->RemoveObserver(this);
   GetInstanceSet().erase(this);
+  if (actor_)
+    actor_->SetDelegate(NULL);
 }
 
 void UpdateScreen::UpdateStatusChanged(UpdateLibrary* library) {
@@ -190,6 +193,7 @@ void UpdateScreen::StartUpdate() {
 }
 
 void UpdateScreen::CancelUpdate() {
+  VLOG(1) << "Forced update cancel";
   ExitUpdate(REASON_UPDATE_CANCELED);
 }
 
@@ -293,4 +297,9 @@ bool UpdateScreen::HasCriticalUpdate() {
   return true;
 }
 
+void UpdateScreen::OnActorDestroyed(UpdateScreenActor* actor) {
+  if (actor_ == actor)
+    actor_ = NULL;
+}
+
 }  // namespace chromeos