Block the autohide of the launcher when 'quiet mode' bubble is shown for notifications.

ash/system/web_notification/web_notification_tray.cc

Index: ash/system/web_notification/web_notification_tray.cc
diff --git a/ash/system/web_notification/web_notification_tray.cc b/ash/system/web_notification/web_notification_tray.cc
index 5e7822fbb8d3c063863e94884f5916ff799a8a78..ce1205491550c544c8a6f6314f2b7d74638666b8 100644
--- a/ash/system/web_notification/web_notification_tray.cc
+++ b/ash/system/web_notification/web_notification_tray.cc
@@ -201,6 +201,10 @@ void WebNotificationTray::UpdateAfterLoginStatusChange(
   UpdateTray();
 }
 
+bool WebNotificationTray::ShouldBlockLauncherAutoHide() const {
+  return IsMessageCenterBubbleVisible() || quiet_mode_bubble() != NULL;
+}
+
 bool WebNotificationTray::IsMessageCenterBubbleVisible() const {
   return (message_center_bubble() &&
           message_center_bubble_->bubble()->IsVisible());