arc: Prevent showing Opt-in UI when it is not expected.

chrome/browser/chromeos/arc/arc_auth_service.cc

Index: chrome/browser/chromeos/arc/arc_auth_service.cc
diff --git a/chrome/browser/chromeos/arc/arc_auth_service.cc b/chrome/browser/chromeos/arc/arc_auth_service.cc
index 435ffdbfd25552ec58fe84aab242275492758f9a..5ab0b220077fe42f6359b43bd41eb2958616cacc 100644
--- a/chrome/browser/chromeos/arc/arc_auth_service.cc
+++ b/chrome/browser/chromeos/arc/arc_auth_service.cc
@@ -409,6 +409,7 @@ void ArcAuthService::RemoveObserver(Observer* observer) {
 
 void ArcAuthService::CloseUI() {
   FOR_EACH_OBSERVER(Observer, observer_list_, OnOptInUIClose());
+  SetUIPage(UIPage::NO_PAGE, base::string16());
   if (!disable_ui_for_testing)

[khmel, 2016/04/23 00:34:40]

I have one more question. There is an idea to prevent pinning this app at all.
Do you know if any legacy functionality for this? I tried to find but seems it
is not available. If not I would say it is too hack-y to implement special for
this case. 

[xiyuan, 2016/04/25 21:14:35]

Have you checked AppListControllerDelegateAsh::GetPinnable[1]? Maybe we should
check also check Extension::ShouldDisplayInAppLauncher and returns NO_PIN if the
exntension does not display in launcher?

[1]:
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/ui/...

[khmel, 2016/04/26 16:37:10]

This might be good point to insert this check.

     ArcAuthNotification::Hide();
 }