views: Extract Widget observer into its own header file.

chrome/browser/ui/views/extensions/extension_popup.cc

 // Copyright (c) 2012 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/ui/views/extensions/extension_popup.h"
 
 #include "base/bind.h"
 #include "base/message_loop.h"
 #include "chrome/browser/debugger/devtools_window.h"
 #include "chrome/browser/extensions/extension_process_manager.h"
 #include "chrome/browser/platform_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/web_contents.h"
 #include "ui/gfx/insets.h"
 #include "ui/views/layout/fill_layout.h"
+#include "ui/views/widget/widget.h"
 
 #if defined(USE_AURA)
 #include "ui/aura/window.h"
 #endif
 
 #if defined(USE_ASH)
 #include "ash/wm/window_animations.h"
 #endif
 
 using content::RenderViewHost;
@@ skipping 180 matching lines @@
 
   if (inspect_with_devtools_) {
     DevToolsWindow::ToggleDevToolsWindow(host()->render_view_host(),
         DEVTOOLS_TOGGLE_ACTION_SHOW_CONSOLE);
   }
 }
 
 void ExtensionPopup::CloseBubble() {
   GetWidget()->Close();
 }