Move CrxFile, FileReader, ExtensionResource to src/extensions.

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/bind.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,
-                       const Callback& callback)
-    : resource_(resource),
-      callback_(callback),
-      origin_loop_(MessageLoop::current()) {
-}
-
-void FileReader::Start() {
-  BrowserThread::PostTask(
-      BrowserThread::FILE, FROM_HERE,
-      base::Bind(&FileReader::ReadFileOnBackgroundThread, this));
-}
-
-FileReader::~FileReader() {}
-
-void FileReader::ReadFileOnBackgroundThread() {
-  std::string data;
-  bool success = file_util::ReadFileToString(resource_.GetFilePath(), &data);
-  origin_loop_->PostTask(FROM_HERE, base::Bind(callback_, success, data));
-}