Enforce WARN_UNUSED_RESULT attribute on Windows

components/update_client/background_downloader_win.cc

 // Copyright 2014 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 "components/update_client/background_downloader_win.h"
 
 #include <atlbase.h>
 #include <atlcom.h>
 
 #include <stdint.h>
 #include <functional>
 #include <iomanip>
 #include <limits>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file_util.h"
+#include "base/macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/win/scoped_co_mem.h"
 #include "components/update_client/utils.h"
 #include "ui/base/win/atl_module.h"
 #include "url/gurl.h"
 
 using base::win::ScopedCoMem;
 using base::win::ScopedComPtr;
@@ skipping 374 matching lines @@
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // The following objects have thread affinity and can't be destroyed on the
   // main thread. The resources managed by these objects are acquired at the
   // beginning of a download and released at the end of the download. Most of
   // the time, when this destructor is called, these resources have been already
   // disposed by. Releasing the ownership here is a NOP. However, if the browser
   // is shutting down while a download is in progress, the timer is active and
   // the interface pointers are valid. Releasing the ownership means leaking
   // these objects and their associated resources.
-  timer_.release();
+  ignore_result(timer_.release());
   bits_manager_.Detach();
   job_.Detach();
 }
 
 void BackgroundDownloader::DoStartDownload(const GURL& url) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   task_runner_->PostTask(FROM_HERE,
                          base::Bind(&BackgroundDownloader::BeginDownload,
                                     base::Unretained(this), url));
@@ skipping 329 matching lines @@
   // must match as a job only contains one file.
   DCHECK(progress.Completed);
   DCHECK_EQ(progress.BytesTotal, progress.BytesTransferred);
 
   response_ = base::FilePath(local_name);
 
   return S_OK;
 }
 
 }  // namespace update_client