Fix HandleJavaScriptDialog.

chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.cc

 // 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.
 
 #include "chrome/browser/ui/javascript_dialogs/javascript_dialog_tab_helper.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/feature_list.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 232 matching lines @@
   return AppModalDialogManager()->RunBeforeUnloadDialog(
       web_contents, is_reload,
       base::Bind(&SaveUnloadUmaStats, engagement_score, callback));
 }
 
 bool JavaScriptDialogTabHelper::HandleJavaScriptDialog(
     content::WebContents* web_contents,
     bool accept,
     const base::string16* prompt_override) {
   if (dialog_) {
-    CloseDialog(accept, prompt_override ? *prompt_override : base::string16(),
+    CloseDialog(accept,
+                prompt_override ? *prompt_override : dialog_->GetUserInput(),
                 DismissalCause::HANDLE_DIALOG_CALLED);
     return true;
   }
 
   // Handle any app-modal dialogs being run by the app-modal dialog system.
   return AppModalDialogManager()->HandleJavaScriptDialog(web_contents, accept,
                                                          prompt_override);
 }
 
 void JavaScriptDialogTabHelper::CancelDialogs(
@@ skipping 84 matching lines @@
   dialog_callback_.Run(success, user_input);
 
   ClearDialogInfo();
 }
 
 void JavaScriptDialogTabHelper::ClearDialogInfo() {
   dialog_.reset();
   dialog_callback_.Reset();
   BrowserList::RemoveObserver(this);
 }