Support Windows native textfield, combobox, etc. in new bubbles.

ui/aura_shell/examples/bubble.cc

 // Copyright (c) 2011 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 "base/utf_string_conversions.h"
 #include "views/bubble/bubble_border.h"
 #include "views/bubble/bubble_delegate.h"
 #include "views/controls/label.h"
 #include "views/layout/fill_layout.h"
 #include "views/widget/widget.h"
@@ skipping 24 matching lines @@
  private:
   string16 label_;
 };
 
 void CreatePointyBubble(views::Widget* parent, const gfx::Point& origin) {
   BubbleConfig config;
   config.label = ASCIIToUTF16("PointyBubble");
   config.color = SK_ColorWHITE;
   config.anchor_point = origin;
   config.arrow = views::BubbleBorder::TOP_LEFT;
-  views::Widget* bubble = views::BubbleDelegateView::CreateBubble(
-      new ExampleBubbleDelegateView(config), parent);
-  bubble->Show();
+  ExampleBubbleDelegateView* bubble_delegate =
+      new ExampleBubbleDelegateView(config);
+  views::BubbleDelegateView::CreateBubble(bubble_delegate, parent);
+  bubble_delegate->Show();
 }
 
 }  // namespace examples
 }  // namespace aura_shell