Make extension callbacks with auto-dismissing dialogs

chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.h

 // Copyright 2016 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_JAVASCRIPT_DIALOGS_JAVASCRIPT_DIALOG_TAB_HELPER_H_
 #define CHROME_BROWSER_UI_JAVASCRIPT_DIALOGS_JAVASCRIPT_DIALOG_TAB_HELPER_H_
 
 #include <memory>
 
 #include "base/callback_forward.h"
@@ skipping 73 matching lines @@
 
   void ClearDialogInfo();
 
   // The dialog being displayed on the observed WebContents.
   base::WeakPtr<JavaScriptDialog> dialog_;
 
   // The type of dialog being displayed. Only valid when |dialog_| is non-null.
   content::JavaScriptDialogType dialog_type_ =
       content::JavaScriptDialogType::JAVASCRIPT_DIALOG_TYPE_ALERT;
 
+  // The WebContents that was marked as showing the dialog.
+  content::WebContents* alerting_web_contents_ = nullptr;
+
   // The callback provided for when the dialog is closed. Usually the dialog
   // itself calls it, but in the cases where the dialog is closed not by the
   // user's input but by a call to |CloseDialog|, this class will call it.
   content::JavaScriptDialogManager::DialogClosedCallback dialog_callback_;
 
   base::Closure dialog_shown_;
 
   DISALLOW_COPY_AND_ASSIGN(JavaScriptDialogTabHelper);
 };
 
 #endif  // CHROME_BROWSER_UI_JAVASCRIPT_DIALOGS_JAVASCRIPT_DIALOG_TAB_HELPER_H_