Pass blocking pool runner to CreateTemporaryFile in SyncFS v2 drive_backend

chrome/browser/sync_file_system/drive_backend/drive_backend_util.cc

 // Copyright 2013 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/browser/sync_file_system/drive_backend/drive_backend_util.h"
 
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/memory/scoped_vector.h"
 #include "base/message_loop/message_loop_proxy.h"
@@ skipping 106 matching lines @@
     const std::string& file_id) {
   scoped_ptr<FileMetadata> file(new FileMetadata);
   file->set_file_id(file_id);
 
   FileDetails* details = file->mutable_details();
   details->set_change_id(change_id);
   details->set_missing(true);
   return file.Pass();
 }
 
-webkit_blob::ScopedFile CreateTemporaryFile() {
+webkit_blob::ScopedFile CreateTemporaryFile(
+    base::TaskRunner* file_task_runner) {
   base::FilePath temp_file_path;
   if (!file_util::CreateTemporaryFile(&temp_file_path))
     return webkit_blob::ScopedFile();
 
   return webkit_blob::ScopedFile(
       temp_file_path,
       webkit_blob::ScopedFile::DELETE_ON_SCOPE_OUT,
-      base::MessageLoopProxy::current().get());
+      file_task_runner);
 }
 
 std::string FileKindToString(FileKind file_kind) {
   switch (file_kind) {
     case FILE_KIND_UNSUPPORTED:
       return "unsupported";
     case FILE_KIND_FILE:
       return "file";
     case FILE_KIND_FOLDER:
       return "folder";
@@ skipping 32 matching lines @@
       oldest.reset(entry);
       candidates[i] = NULL;
     }
   }
 
   return oldest.Pass();
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system