Move BrowserThread to content namespace.

chrome/browser/extensions/file_reader.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/browser/extensions/file_reader.h"
 
 #include "base/file_util.h"
 #include "base/message_loop.h"
 #include "chrome/common/extensions/extension_resource.h"
 #include "content/public/browser/browser_thread.h"
 
+using content::BrowserThread;
+
 FileReader::FileReader(const ExtensionResource& resource, Callback* callback)
     : resource_(resource),
       callback_(callback),
       origin_loop_(MessageLoop::current()) {
   DCHECK(callback_);
 }
 
 void FileReader::Start() {
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
       NewRunnableMethod(this, &FileReader::ReadFileOnBackgroundThread));
 }
 
 FileReader::~FileReader() {}
 
 void FileReader::ReadFileOnBackgroundThread() {
   std::string data;
   bool success = file_util::ReadFileToString(resource_.GetFilePath(), &data);
   origin_loop_->PostTask(FROM_HERE, NewRunnableMethod(
       this, &FileReader::RunCallback, success, data));
 }
 
 void FileReader::RunCallback(bool success, const std::string& data) {
   callback_->Run(success, data);
   delete callback_;
 }