Fix DownloadsDOMHandler::OnDownloadDestroyed

chrome/browser/ui/webui/downloads_dom_handler.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/webui/downloads_dom_handler.h"
 
 #include <algorithm>
 #include <functional>
 
 #include "base/basictypes.h"
@@ skipping 174 matching lines @@
   results_value.Append(download_util::CreateDownloadItemValue(download, id));
   web_ui()->CallJavascriptFunction("downloadUpdated", results_value);
 }
 
 void DownloadsDOMHandler::OnDownloadDestroyed(
     content::DownloadItem* download) {
   download->RemoveObserver(this);
   OrderedDownloads::iterator it = std::find(download_items_.begin(),
                                             download_items_.end(),
                                             download);
-  *it = NULL;
+  if (it != download_items_.end())
+    *it = NULL;
   // A later ModelChanged() notification will change the WebUI's
   // view of the downloads list.
 }
 
 // A download has started or been deleted. Query our DownloadManager for the
 // current set of downloads.
 void DownloadsDOMHandler::ModelChanged(content::DownloadManager* manager) {
   DCHECK(manager == download_manager_ ||
          manager == original_profile_download_manager_);
 
@@ skipping 201 matching lines @@
 }
 
 content::DownloadItem* DownloadsDOMHandler::GetDownloadByValue(
     const ListValue* args) {
   int id;
   if (ExtractIntegerValue(args, &id)) {
     return GetDownloadById(id);
   }
   return NULL;
 }