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 164 matching lines @@
   bound_net_log_.AddEvent(net::NetLog::TYPE_DOWNLOAD_FILE_DETACHED);
 }
 
 void BaseFile::Cancel() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   DCHECK(!detached_);
 
   bound_net_log_.AddEvent(net::NetLog::TYPE_CANCELLED);
 
   Close();
+  Detach();

[Randy Smith (Not in Mondays), 2014/05/23 19:05:21]

Hmmm.  I'm a bit uncomfortable with the abstractions in this file; in my mind
"detached_" should mean "don't have anything to do with the underlying file
anymore" and nothing should be allowed to happen in that state (with the
possible exception of Rename(), but even there, it seems like that's a good
invariant to keep).  I.e once you've detached, destruction should be a no-op. 
That's larger (if still minor) cleanup, so I'm not requesting that you do it. 
But I think I would like the detach to be after the conditional, below.  

 
   if (!full_path_.empty()) {
     bound_net_log_.AddEvent(net::NetLog::TYPE_DOWNLOAD_FILE_DELETED);
 
     base::DeleteFile(full_path_, false);
   }
 }
 
 void BaseFile::Finish() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
@@ skipping 141 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