Pull AsyncApiFunction out of src/chrome

chrome/browser/extensions/api/api_function.h

-// 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.
-
-#ifndef CHROME_BROWSER_EXTENSIONS_API_API_FUNCTION_H_
-#define CHROME_BROWSER_EXTENSIONS_API_API_FUNCTION_H_
-
-#include "chrome/browser/extensions/chrome_extension_function.h"
-#include "content/public/browser/browser_thread.h"
-
-namespace extensions {
-
-// Base class for API functions. TODO(miket): there isn't much here anymore
-// since the removal of ApiResourceEventRouter. Should we promote all its
-// subclasses to UIThreadExtensionFunctions?
-class ApiFunction : public ChromeAsyncExtensionFunction {
- protected:
-  ApiFunction();
-  virtual ~ApiFunction();
-};
-
-// AsyncApiFunction provides convenient thread management for APIs that need to
-// do essentially all their work on a thread other than the UI thread.
-class AsyncApiFunction : public ApiFunction {
- protected:
-  AsyncApiFunction();
-  virtual ~AsyncApiFunction();
-
-  // Like Prepare(). A useful place to put common work in an ApiFunction
-  // superclass that multiple API functions want to share.
-  virtual bool PrePrepare();
-
-  // Set up for work (e.g., validate arguments). Guaranteed to happen on UI
-  // thread.
-  virtual bool Prepare() = 0;
-
-  // Do actual work. Guaranteed to happen on the thread specified in
-  // work_thread_id_.
-  virtual void Work();
-
-  // Start the asynchronous work. Guraranteed to happen on requested thread.
-  virtual void AsyncWorkStart();
-
-  // Notify AsyncIOApiFunction that the work is completed
-  void AsyncWorkCompleted();
-
-  // Respond. Guaranteed to happen on UI thread.
-  virtual bool Respond() = 0;
-
-  // ExtensionFunction::RunImpl()
-  virtual bool RunImpl() OVERRIDE;
-
- protected:
-  void set_work_thread_id(content::BrowserThread::ID work_thread_id) {
-    work_thread_id_ = work_thread_id;
-  }
-
- private:
-  void WorkOnWorkThread();
-  void RespondOnUIThread();
-
-  // If you don't want your Work() method to happen on the IO thread, then set
-  // this to the thread that you do want, preferably in Prepare().
-  content::BrowserThread::ID work_thread_id_;
-};
-
-}  // namespace extensions
-
-#endif  // CHROME_BROWSER_EXTENSIONS_API_API_FUNCTION_H_