Handle the case where IAttachmentExecute::Save() deletes a downloaded file.

content/browser/download/download_file_manager.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 "content/browser/download/download_file_manager.h"
 
 #include <set>
 #include <string>
 
 #include "base/bind.h"
@@ skipping 84 matching lines @@
 
   DownloadFile* download_file = it->second;
   VLOG(20) << __FUNCTION__ << "()"
            << " download_file = " << download_file->DebugString();
   download_file->Cancel();
 
   EraseDownload(global_id);
 }
 
 void DownloadFileManager::CompleteDownload(
-    DownloadId global_id, const base::Closure& callback) {
+    DownloadId global_id, const CompleteCompletionCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 
   if (!ContainsKey(downloads_, global_id))
     return;
 
   DownloadFile* download_file = downloads_[global_id];
 
   VLOG(20) << " " << __FUNCTION__ << "()"
            << " id = " << global_id
            << " download_file = " << download_file->DebugString();
@@ skipping 58 matching lines @@
   DownloadFile* download_file = downloads_[global_id];
 
   VLOG(20) << " " << __FUNCTION__ << "()"
            << " id = " << global_id
            << " download_file = " << download_file->DebugString();
 
   downloads_.erase(global_id);
 
   delete download_file;
 }