[SyncFS] Make task invocation in SyncTaskRunner async

chrome/browser/sync_file_system/drive_backend/conflict_resolver_unittest.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/conflict_resolver.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/file_util.h"
 #include "base/files/scoped_temp_dir.h"
@@ skipping 63 matching lines @@
         NULL,
         base::MessageLoopProxy::current(),
         base::MessageLoopProxy::current(),
         base::MessageLoopProxy::current()));
     context_->SetRemoteChangeProcessor(remote_change_processor_.get());
 
     RegisterSyncableFileSystem();
 
     sync_task_manager_.reset(new SyncTaskManager(
         base::WeakPtr<SyncTaskManager::Client>(),
-        10 /* maximum_background_task */));
+        10 /* maximum_background_task */,
+        base::MessageLoopProxy::current()));
     sync_task_manager_->Initialize(SYNC_STATUS_OK);
   }
 
   virtual void TearDown() OVERRIDE {
     sync_task_manager_.reset();
     RevokeSyncableFileSystem();
     fake_drive_helper_.reset();
     context_.reset();
     base::RunLoop().RunUntilIdle();
   }
@@ skipping 415 matching lines @@
 
   EXPECT_EQ(4, CountParents(file));
 
   EXPECT_EQ(SYNC_STATUS_OK, RunConflictResolver());
 
   EXPECT_EQ(1, CountParents(file));
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system