Move extensions bindings code out of //chrome

chrome/renderer/extensions/context_menus_custom_bindings.cc

-// Copyright (c) 2012 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/renderer/extensions/context_menus_custom_bindings.h"
-
-#include "base/bind.h"
-#include "content/public/renderer/render_thread.h"
-#include "extensions/common/extension_messages.h"
-#include "grit/renderer_resources.h"
-#include "v8/include/v8.h"
-
-namespace {
-
-void GetNextContextMenuId(const v8::FunctionCallbackInfo<v8::Value>& args) {
-  int context_menu_id = -1;
-  content::RenderThread::Get()->Send(
-      new ExtensionHostMsg_GenerateUniqueID(&context_menu_id));
-  args.GetReturnValue().Set(static_cast<int32_t>(context_menu_id));
-}
-
-}  // namespace
-
-namespace extensions {
-
-ContextMenusCustomBindings::ContextMenusCustomBindings(
-    Dispatcher* dispatcher, ChromeV8Context* context)
-    : ChromeV8Extension(dispatcher, context) {
-  RouteFunction("GetNextContextMenuId", base::Bind(&GetNextContextMenuId));
-}
-
-}  // extensions