Move ReadFileToString to the base namespace.

chrome/browser/sync_file_system/drive_backend/fake_drive_service_helper.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/fake_drive_service_helper.h"
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/threading/sequenced_worker_pool.h"
@@ skipping 239 matching lines @@
   EXPECT_TRUE(file_util::CreateTemporaryFileInDir(temp_dir_, &temp_file));
   fake_drive_service_->DownloadFile(
       temp_file, file->resource_id(),
       base::Bind(&DownloadResultCallback, &error),
       google_apis::GetContentCallback(),
       google_apis::ProgressCallback());
   FlushMessageLoop();
   if (error != google_apis::HTTP_SUCCESS)
     return error;
 
-  return file_util::ReadFileToString(temp_file, file_content)
+  return base::ReadFileToString(temp_file, file_content)
       ? google_apis::HTTP_SUCCESS : google_apis::GDATA_FILE_ERROR;
 }
 
 GDataErrorCode FakeDriveServiceHelper::CompleteListing(
     scoped_ptr<ResourceList> list,
     ScopedVector<ResourceEntry>* entries) {
   while (true) {
     entries->reserve(entries->size() + list->entries().size());
     for (ScopedVector<ResourceEntry>::iterator itr =
          list->mutable_entries()->begin();
@@ skipping 34 matching lines @@
 }
 
 void FakeDriveServiceHelper::FlushMessageLoop() {
   base::MessageLoop::current()->RunUntilIdle();
   content::BrowserThread::GetBlockingPool()->FlushForTesting();
   base::MessageLoop::current()->RunUntilIdle();
 }
 
 }  // namespace drive_backend
 }  // namespace sync_file_system