Added WARN_UNUSED_RESULT to ScopedTempDir methods.

chrome/service/service_utility_process_host.cc

 // Copyright (c) 2011 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 "chrome/service/service_utility_process_host.h"
 
 #include "app/app_switches.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/message_loop.h"
@@ skipping 180 matching lines @@
   IPC_END_MESSAGE_MAP_EX()
   return handled;
 }
 
 void ServiceUtilityProcessHost::Client::MetafileAvailable(
     const FilePath& metafile_path,
     int highest_rendered_page_number) {
   // The metafile was created in a temp folder which needs to get deleted after
   // we have processed it.
   ScopedTempDir scratch_metafile_dir;
-  scratch_metafile_dir.Set(metafile_path.DirName());
+  if (!scratch_metafile_dir.Set(metafile_path.DirName()))
+    LOG(WARNING) << "Unable to set scratch metafile directory";
 #if defined(OS_WIN)
   printing::NativeMetafile metafile;
   if (!metafile.CreateFromFile(metafile_path)) {
     OnRenderPDFPagesToMetafileFailed();
   } else {
     OnRenderPDFPagesToMetafileSucceeded(metafile, highest_rendered_page_number);
     // Close it so that ScopedTempDir can delete the folder.
     metafile.CloseEmf();
   }
 #endif  // defined(OS_WIN)
 }