System bubbles work with webui login display

chrome/browser/chromeos/setting_level_bubble.cc

Index: chrome/browser/chromeos/setting_level_bubble.cc
diff --git a/chrome/browser/chromeos/setting_level_bubble.cc b/chrome/browser/chromeos/setting_level_bubble.cc
index 8af98bf6e8c55162a2b9e946e9ecd6469218c9e5..e6b5176909a6f3512c0241da407c700a605bfee8 100644
--- a/chrome/browser/chromeos/setting_level_bubble.cc
+++ b/chrome/browser/chromeos/setting_level_bubble.cc
@@ -9,6 +9,7 @@
 #include "base/timer.h"
 #include "chrome/browser/chromeos/login/background_view.h"
 #include "chrome/browser/chromeos/login/login_utils.h"
+#include "chrome/browser/chromeos/login/webui_login_display.h"
 #include "chrome/browser/chromeos/setting_level_bubble_view.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/browser.h"
@@ -65,10 +66,10 @@ static views::Widget* GetToplevelWidget() {
       window = GTK_WINDOW(background->GetNativeWindow());
   }
 
-  if (!window)
-    return NULL;
-
-  return views::Widget::GetWidgetForNativeWindow(window);
+  if (window)
+    return views::Widget::GetWidgetForNativeWindow(window);
+  else
+    return WebUILoginDisplay::GetLoginWindow();
 }
 
 SettingLevelBubble::SettingLevelBubble(SkBitmap* increase_icon,
@@ -102,8 +103,10 @@ void SettingLevelBubble::ShowBubble(int percent) {
 
   if (!bubble_) {
     views::Widget* parent_widget = GetToplevelWidget();
-    if (parent_widget == NULL)
+    if (parent_widget == NULL) {
+      LOG(WARNING) << "Unable to locate parent widget to display a bubble";
       return;
+    }
     DCHECK(view_ == NULL);
     view_ = new SettingLevelBubbleView;
     view_->Init(icon, previous_percent_);