Move blink scheduler implementation into a component

content/child/webthread_base.h

-// Copyright 2014 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_CHILD_WEBTHREAD_BASE_H_
-#define CONTENT_CHILD_WEBTHREAD_BASE_H_
-
-#include <map>
-
-#include "base/memory/scoped_ptr.h"
-#include "base/threading/thread.h"
-#include "content/common/content_export.h"
-#include "third_party/WebKit/public/platform/WebThread.h"
-
-namespace blink {
-class WebTraceLocation;
-}
-
-namespace content {
-class SingleThreadIdleTaskRunner;
-
-class CONTENT_EXPORT WebThreadBase : public blink::WebThread {
- public:
-  virtual ~WebThreadBase();
-
-  // blink::WebThread implementation.
-  virtual bool isCurrentThread() const;
-  virtual blink::PlatformThreadId threadId() const = 0;
-
-  virtual void postTask(const blink::WebTraceLocation& location, Task* task);
-  virtual void postDelayedTask(const blink::WebTraceLocation& location,
-                               Task* task,
-                               long long delay_ms);
-  virtual void postIdleTask(const blink::WebTraceLocation& location,
-                            IdleTask* idle_task);
-  virtual void postIdleTaskAfterWakeup(const blink::WebTraceLocation& location,
-                                       IdleTask* idle_task);
-
-  virtual void enterRunLoop();
-  virtual void exitRunLoop();
-
-  virtual void addTaskObserver(TaskObserver* observer);
-  virtual void removeTaskObserver(TaskObserver* observer);
-
-  // Returns the base::Bind-compatible task runner for posting tasks to this
-  // thread. Can be called from any thread.
-  virtual base::SingleThreadTaskRunner* TaskRunner() const = 0;
-
-  // Returns the base::Bind-compatible task runner for posting idle tasks to
-  // this thread. Can be called from any thread.
-  virtual SingleThreadIdleTaskRunner* IdleTaskRunner() const = 0;
-
- protected:
-  class TaskObserverAdapter;
-
-  WebThreadBase();
-
-  // Returns the underlying MessageLoop for this thread. Only used for entering
-  // and exiting a nested run loop. Only called on the thread that the
-  // WebThread belongs to.
-  virtual base::MessageLoop* MessageLoop() const = 0;
-
-  virtual void AddTaskObserverInternal(
-      base::MessageLoop::TaskObserver* observer);
-  virtual void RemoveTaskObserverInternal(
-      base::MessageLoop::TaskObserver* observer);
-
-  static void RunWebThreadTask(scoped_ptr<blink::WebThread::Task> task);
-  static void RunWebThreadIdleTask(
-      scoped_ptr<blink::WebThread::IdleTask> idle_task,
-      base::TimeTicks deadline);
-
- private:
-  typedef std::map<TaskObserver*, TaskObserverAdapter*> TaskObserverMap;
-  TaskObserverMap task_observer_map_;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_CHILD_WEBTHREAD_BASE_H_