Update WebTask in chromium c++ style

content/shell/renderer/test_runner/WebTask.h

-// Copyright 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.
-
-#ifndef CONTENT_SHELL_RENDERER_TEST_RUNNER_WEBTASK_H_
-#define CONTENT_SHELL_RENDERER_TEST_RUNNER_WEBTASK_H_
-
-#include <vector>
-
-namespace content {
-
-class WebTaskList;
-
-// WebTask represents a task which can run by WebTestDelegate::postTask() or
-// WebTestDelegate::postDelayedTask().
-class WebTask {
-public:
-    explicit WebTask(WebTaskList*);
-    virtual ~WebTask();
-
-    // The main code of this task.
-    // An implementation of run() should return immediately if cancel() was called.
-    virtual void run() = 0;
-    virtual void cancel() = 0;
-
-protected:
-    WebTaskList* m_taskList;
-};
-
-class WebTaskList {
-public:
-    WebTaskList();
-    ~WebTaskList();
-    void registerTask(WebTask*);
-    void unregisterTask(WebTask*);
-    void revokeAll();
-
-private:
-    std::vector<WebTask*> m_tasks;
-};
-
-// A task containing an object pointer of class T. Derived classes should
-// override runIfValid() which in turn can safely invoke methods on the
-// m_object. The Class T must have "WebTaskList* mutable_task_list()".
-template<class T>
-class WebMethodTask : public WebTask {
-public:
-    explicit WebMethodTask(T* object)
-        : WebTask(object->mutable_task_list())
-        , m_object(object)
-    {
-    }
-
-    virtual ~WebMethodTask() { }
-
-    virtual void run()
-    {
-        if (m_object)
-            runIfValid();
-    }
-
-    virtual void cancel()
-    {
-        m_object = 0;
-        m_taskList->unregisterTask(this);
-        m_taskList = 0;
-    }
-
-    virtual void runIfValid() = 0;
-
-protected:
-    T* m_object;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_SHELL_RENDERER_TEST_RUNNER_WEBTASK_H_