Move a bunch of child-only code from content/common to content/child

content/common/thread_safe_sender.cc

-// Copyright (c) 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 "content/common/thread_safe_sender.h"
-
-#include "base/message_loop_proxy.h"
-#include "content/common/child_thread.h"
-#include "ipc/ipc_sync_message_filter.h"
-
-namespace content {
-
-ThreadSafeSender::ThreadSafeSender(base::MessageLoopProxy* main_loop,
-                                   IPC::SyncMessageFilter* sync_filter)
-    : main_loop_(main_loop), sync_filter_(sync_filter) {
-}
-
-ThreadSafeSender::~ThreadSafeSender() {
-}
-
-bool ThreadSafeSender::Send(IPC::Message* msg) {
-  if (main_loop_->BelongsToCurrentThread())
-    return ChildThread::current()->Send(msg);
-  return sync_filter_->Send(msg);
-}
-
-}  // namespace content