Enforce WARN_UNUSED_RESULT attribute on Windows

components/update_client/background_downloader_win.cc

Index: components/update_client/background_downloader_win.cc
diff --git a/components/update_client/background_downloader_win.cc b/components/update_client/background_downloader_win.cc
index 262824a11485019b5d049581fdba543ed22079a1..1e449d3bf5d8e0ea3dccbe62b59ea717e0a1d8dc 100644
--- a/components/update_client/background_downloader_win.cc
+++ b/components/update_client/background_downloader_win.cc
@@ -16,6 +16,7 @@
 #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"
@@ -410,7 +411,7 @@ BackgroundDownloader::~BackgroundDownloader() {
   // 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();
 }