Add more of the server-side plumbing for extension APIs. Also

chrome/browser/extensions/extension_api_handler.h

-// Copyright (c) 2009 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.
-
-#ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_APIS_H_
-#define CHROME_BROWSER_EXTENSIONS_EXTENSION_APIS_H_
-
-#include <string>
-
-class RenderViewHost;
-
-// ExtensionAPIHandler is the top-level entry point for extension callbacks
-// in the browser process. It lives on the UI thread.
-class ExtensionAPIHandler {
- public:
-  ExtensionAPIHandler(RenderViewHost* render_view_host);
-
-  // Handle a request to perform some synchronous API.
-  // TODO(aa): args should be a Value object.
-  void HandleRequest(const std::string& name, const std::string& args,
-                     int callback_id);
-
- private:
-  // TODO(aa): Once there can be APIs that are asynchronous wrt the browser's UI
-  // thread, we may have to have to do something about this raw pointer.
-  RenderViewHost* render_view_host_;
-};
-
-#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_APIS_H_