Fix the issue introduced by hooking window.onbeforeunload in WebDialogView which breaks WebDialogUI…

ui/views/controls/webview/web_dialog_view.h

 // 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.
 
 #ifndef UI_VIEWS_CONTROLS_WEBVIEW_WEB_DIALOG_VIEW_H_
 #define UI_VIEWS_CONTROLS_WEBVIEW_WEB_DIALOG_VIEW_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 68 matching lines @@
   virtual GURL GetDialogContentURL() const OVERRIDE;
   virtual void GetWebUIMessageHandlers(
       std::vector<content::WebUIMessageHandler*>* handlers) const OVERRIDE;
   virtual void GetDialogSize(gfx::Size* size) const OVERRIDE;
   virtual void GetMinimumDialogSize(gfx::Size* size) const OVERRIDE;
   virtual std::string GetDialogArgs() const OVERRIDE;
   virtual void OnDialogShown(
       content::WebUI* webui,
       content::RenderViewHost* render_view_host) OVERRIDE;
   virtual void OnDialogClosed(const std::string& json_retval) OVERRIDE;
+  virtual void OnDialogCloseFromWebUI(
+      const std::string& json_retval) OVERRIDE;
   virtual void OnCloseContents(content::WebContents* source,
                                bool* out_close_dialog) OVERRIDE;
   virtual bool ShouldShowDialogTitle() const OVERRIDE;
   virtual bool HandleContextMenu(
       const content::ContextMenuParams& params) OVERRIDE;
 
   // Overridden from content::WebContentsDelegate:
   virtual void MoveContents(content::WebContents* source,
                             const gfx::Rect& pos) OVERRIDE;
   virtual void HandleKeyboardEvent(
@@ skipping 34 matching lines @@
   views::WebView* web_view_;
 
   // Whether user is attempting to close the dialog and we are processing
   // beforeunload event.
   bool is_attempting_close_dialog_;
 
   // Whether beforeunload event has been fired and we have finished processing
   // beforeunload event.
   bool before_unload_fired_;
 
+  // Whether the dialog is closed from WebUI in response to a "DialogClose"
+  // message.
+  bool closed_via_webui_;
+
+  // A json string returned to WebUI from a "DialogClosed" message.
+  std::string dialog_close_retval_;
+
   DISALLOW_COPY_AND_ASSIGN(WebDialogView);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_WEBVIEW_WEB_DIALOG_VIEW_H_