Close tray bubble before disabling UI for sign-in.

chrome/browser/chromeos/login/ui/webui_login_view.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/chromeos/login/ui/webui_login_view.h"
 
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray.h"
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 330 matching lines @@
       tray->SetVisible(visible);
       tray->GetWidget()->Show();
     } else {
       tray->GetWidget()->Hide();
     }
   }
 }
 
 void WebUILoginView::SetUIEnabled(bool enabled) {
   forward_keyboard_event_ = enabled;
-  ash::Shell::GetInstance()->GetPrimarySystemTray()->SetEnabled(enabled);
+  ash::SystemTray* tray = ash::Shell::GetInstance()->GetPrimarySystemTray();
+
+  // We disable the UI to prevent user from interracting with UI elements,
+  // particullary with the system tray menu. However, in case if the system tray
+  // bubble is opened at this point, it remains opened and interactictive even
+  // after SystemTray::SetEnabled(false) call, which can be dangerous
+  // (http://crbug.com/497080). Close the menu to fix it. Calling
+  // SystemTray::SetEnabled(false) guarantees, that the menu will not be opened
+  // until the UI is enabled again.
+  if (!enabled && tray->HasSystemBubble())
+    tray->CloseSystemBubble();
+
+  tray->SetEnabled(enabled);
 }
 
 void WebUILoginView::AddFrameObserver(FrameObserver* frame_observer) {
   DCHECK(frame_observer);
   DCHECK(!frame_observer_list_.HasObserver(frame_observer));
   frame_observer_list_.AddObserver(frame_observer);
 }
 
 void WebUILoginView::RemoveFrameObserver(FrameObserver* frame_observer) {
   DCHECK(frame_observer);
@@ skipping 152 matching lines @@
   webui_visible_ = true;
 }
 
 void WebUILoginView::ReturnFocus(bool reverse) {
   // Return the focus to the web contents.
   webui_login_->web_contents()->FocusThroughTabTraversal(reverse);
   GetWidget()->Activate();
 }
 
 }  // namespace chromeos