Avoid trying to delete a non-existent file.

content/browser/download/base_file.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/base_file.h"
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/files/file.h"
 #include "base/format_macros.h"
@@ skipping 167 matching lines @@
 void BaseFile::Cancel() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   DCHECK(!detached_);
 
   bound_net_log_.AddEvent(net::NetLog::TYPE_CANCELLED);
 
   Close();
 
   if (!full_path_.empty()) {
     bound_net_log_.AddEvent(net::NetLog::TYPE_DOWNLOAD_FILE_DELETED);
-
     base::DeleteFile(full_path_, false);
   }
+
+  Detach();
 }
 
 void BaseFile::Finish() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 
   if (calculate_hash_)
     secure_hash_->Finish(sha256_hash_, crypto::kSHA256Length);
 
   Close();
 }
@@ skipping 135 matching lines @@
     const char* operation,
     int os_error,
     DownloadInterruptReason reason) {
   bound_net_log_.AddEvent(
       net::NetLog::TYPE_DOWNLOAD_FILE_ERROR,
       base::Bind(&FileInterruptedNetLogCallback, operation, os_error, reason));
   return reason;
 }
 
 }  // namespace content