Update WebTask in chromium c++ style

content/shell/renderer/test_runner/web_task.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_WEB_TASK_H_
+#define CONTENT_SHELL_RENDERER_TEST_RUNNER_WEB_TASK_H_
+
+#include <vector>
+
+#include "base/macros.h"
+
+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* task_list_;
+};
+
+class WebTaskList {
+ public:
+  WebTaskList();
+  ~WebTaskList();
+  void RegisterTask(WebTask*);
+  void UnregisterTask(WebTask*);
+  void RevokeAll();
+
+ private:
+  std::vector<WebTask*> tasks_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebTaskList);
+};
+
+// A task containing an object pointer of class T. Derived classes should
+// override RunIfValid() which in turn can safely invoke methods on the
+// 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()), object_(object) {}
+
+  virtual ~WebMethodTask() {}
+
+  virtual void run() {
+    if (object_)
+      RunIfValid();
+  }
+
+  virtual void cancel() {
+    object_ = 0;
+    task_list_->UnregisterTask(this);
+    task_list_ = 0;
+  }
+
+  virtual void RunIfValid() = 0;
+
+ protected:
+  T* object_;
+};
+
+}  // namespace content
+
+#endif  // CONTENT_SHELL_RENDERER_TEST_RUNNER_WEB_TASK_H_