Revert of ServiceWorker: Introduce SWMessageSender in order to mock IPC messaging

content/child/service_worker/service_worker_message_sender.cc

-// Copyright 2015 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 "content/child/service_worker/service_worker_message_sender.h"
-
-#include "content/child/thread_safe_sender.h"
-
-namespace content {
-
-ServiceWorkerMessageSender::ServiceWorkerMessageSender(
-    ThreadSafeSender* thread_safe_sender)
-    : thread_safe_sender_(thread_safe_sender) {
-}
-
-bool ServiceWorkerMessageSender::Send(IPC::Message* message) {
-  return thread_safe_sender_->Send(message);
-}
-
-ServiceWorkerMessageSender::~ServiceWorkerMessageSender() {
-}
-
-}  // namespace content