drive: Rewrite UpdateOpreation to access cache/metadata on the blocking pool

chrome/browser/chromeos/drive/file_system/operations.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 "chrome/browser/chromeos/drive/file_system/operations.h"
 
 #include "base/callback.h"
 #include "chrome/browser/chromeos/drive/file_system/copy_operation.h"
 #include "chrome/browser/chromeos/drive/file_system/create_directory_operation.h"
 #include "chrome/browser/chromeos/drive/file_system/create_file_operation.h"
@@ skipping 45 matching lines @@
                                                        metadata,
                                                        cache));
   move_operation_.reset(
       new MoveOperation(observer, scheduler, metadata));
   remove_operation_.reset(
       new RemoveOperation(observer, scheduler, metadata, cache));
   touch_operation_.reset(
       new TouchOperation(blocking_task_runner, observer, scheduler, metadata));
   download_operation_.reset(new DownloadOperation(
       blocking_task_runner, observer, scheduler, metadata, cache));
-  update_operation_.reset(
-      new UpdateOperation(observer, scheduler, metadata, cache));
+  update_operation_.reset(new UpdateOperation(blocking_task_runner,
+                                              observer,
+                                              scheduler,
+                                              metadata,
+                                              cache));
   search_operation_.reset(
       new SearchOperation(blocking_task_runner, scheduler, metadata));
 }
 
 void Operations::Copy(const base::FilePath& src_file_path,
                       const base::FilePath& dest_file_path,
                       const FileOperationCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!callback.is_null());
 
@@ skipping 103 matching lines @@
                         const GURL& next_feed,
                         const SearchOperationCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(!callback.is_null());
 
   search_operation_->Search(search_query, next_feed, callback);
 }
 
 }  // namespace file_system
 }  // namespace drive