Oust BubbleWindow from ExtensionDialog, use chromeos::BubbleFrameView directly.

chrome/browser/chromeos/frame/bubble_window_gtk.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 "chrome/browser/chromeos/frame/bubble_window.h"
 
 #include <gtk/gtk.h>
 
 #include "chrome/browser/chromeos/frame/bubble_frame_view.h"
 #include "ui/gfx/skia_utils_gtk.h"
@@ skipping 23 matching lines @@
   // manager should only show the window after getting notified. And we
   // should only notify window manager after at least one paint is done.
   // TODO(xiyuan): Figure out the right fix.
   gtk_widget_realize(GetNativeView());
   gdk_window_set_back_pixmap(GetNativeView()->window, NULL, FALSE);
   gtk_widget_realize(window_contents());
   gdk_window_set_back_pixmap(window_contents()->window, NULL, FALSE);
 }
 
 views::NonClientFrameView* BubbleWindow::CreateNonClientFrameView() {
-  views::Widget* window = GetWidget();
-  return new BubbleFrameView(window, window->widget_delegate(), style_);
+  return new BubbleFrameView(GetWidget()->widget_delegate(), style_);
 }
 
 views::Widget* BubbleWindow::Create(
     gfx::NativeWindow parent,
     DialogStyle style,
     views::WidgetDelegate* widget_delegate) {
   views::Widget* window = new views::Widget;
   BubbleWindow* bubble_window = new BubbleWindow(window, style);
   views::Widget::InitParams params;
   params.delegate = widget_delegate;
   params.native_widget = bubble_window;
   params.parent = GTK_WIDGET(parent);
   params.bounds = gfx::Rect();
   window->Init(params);
 
   return window;
 }
 
 }  // namespace chromeos