Fix a crash on WebViewFocusHelper destruction.

chrome/browser/ui/webui/constrained_web_dialog_ui.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 CHROME_BROWSER_UI_WEBUI_CONSTRAINED_WEB_DIALOG_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_CONSTRAINED_WEB_DIALOG_UI_H_
 
 #include "base/compiler_specific.h"
 #include "components/web_modal/native_web_contents_modal_dialog.h"
 #include "content/public/browser/web_ui_controller.h"
@@ skipping 64 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(ConstrainedWebDialogUI);
 };
 
 // Create a constrained HTML dialog. The actual object that gets created
 // is a ConstrainedWebDialogDelegate, which later triggers construction of a
 // ConstrainedWebDialogUI object.
 // |browser_context| is used to construct the constrained HTML dialog's
 //                   WebContents.
 // |delegate| controls the behavior of the dialog.
-// |tab_delegate| is optional, pass one in to use a custom
-//                WebDialogWebContentsDelegate with the dialog, or NULL to
-//                use the default one. The dialog takes ownership of
-//                |tab_delegate|.
 // |overshadowed| is the tab being overshadowed by the dialog.
 ConstrainedWebDialogDelegate* CreateConstrainedWebDialog(
     content::BrowserContext* browser_context,
     ui::WebDialogDelegate* delegate,
-    ui::WebDialogWebContentsDelegate* tab_delegate,
     content::WebContents* overshadowed);
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CONSTRAINED_WEB_DIALOG_UI_H_