Move blink scheduler implementation into a component

content/renderer/scheduler/renderer_scheduler.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_RENDERER_SCHEDULER_RENDERER_SCHEDULER_H_
-#define CONTENT_RENDERER_SCHEDULER_RENDERER_SCHEDULER_H_
-
-#include "base/message_loop/message_loop.h"
-#include "content/child/scheduler/child_scheduler.h"
-#include "content/child/scheduler/single_thread_idle_task_runner.h"
-#include "content/common/content_export.h"
-#include "third_party/WebKit/public/web/WebInputEvent.h"
-
-namespace cc {
-struct BeginFrameArgs;
-}
-
-namespace content {
-
-class CONTENT_EXPORT RendererScheduler : public ChildScheduler {
- public:
-  ~RendererScheduler() override;
-  static scoped_ptr<RendererScheduler> Create();
-
-  // Returns the compositor task runner.
-  virtual scoped_refptr<base::SingleThreadTaskRunner>
-  CompositorTaskRunner() = 0;
-
-  // Returns the loading task runner.  This queue is intended for tasks related
-  // to resource dispatch, foreground HTML parsing, etc...
-  virtual scoped_refptr<base::SingleThreadTaskRunner> LoadingTaskRunner() = 0;
-
-  // Returns the timer task runner.  This queue is intended for DOM Timers.
-  virtual scoped_refptr<base::SingleThreadTaskRunner> TimerTaskRunner() = 0;
-
-  // Called to notify about the start of an extended period where no frames
-  // need to be drawn. Must be called from the main thread.
-  virtual void BeginFrameNotExpectedSoon() = 0;
-
-  // Called to notify about the start of a new frame.  Must be called from the
-  // main thread.
-  virtual void WillBeginFrame(const cc::BeginFrameArgs& args) = 0;
-
-  // Called to notify that a previously begun frame was committed. Must be
-  // called from the main thread.
-  virtual void DidCommitFrameToCompositor() = 0;
-
-  // Tells the scheduler that the system received an input event. Called by the
-  // compositor (impl) thread.
-  virtual void DidReceiveInputEventOnCompositorThread(
-      const blink::WebInputEvent& web_input_event) = 0;
-
-  // Tells the scheduler that the system is displaying an input animation (e.g.
-  // a fling). Called by the compositor (impl) thread.
-  virtual void DidAnimateForInputOnCompositorThread() = 0;
-
-  // Tells the scheduler that all render widgets managed by this renderer
-  // process have been hidden. The renderer is assumed to be visible when the
-  // scheduler is constructed. Must be called on the main thread.
-  virtual void OnRendererHidden() = 0;
-
-  // Tells the scheduler that at least one render widget managed by this
-  // renderer process has become visible and the renderer is no longer hidden.
-  // The renderer is assumed to be visible when the scheduler is constructed.
-  // Must be called on the main thread.
-  virtual void OnRendererVisible() = 0;
-
-  // Returns true if the scheduler has reason to believe that high priority work
-  // may soon arrive on the main thread, e.g., if gesture events were observed
-  // recently.
-  // Must be called from the main thread.
-  virtual bool IsHighPriorityWorkAnticipated() = 0;
-
-  // Suspends the timer queue and increments the timer queue suspension count.
-  // May only be called from the main thread.
-  virtual void SuspendTimerQueue() = 0;
-
-  // Decrements the timer queue suspension count and re-enables the timer queue
-  // if the suspension count is zero and the current schduler policy allows it.
-  virtual void ResumeTimerQueue() = 0;
-
- protected:
-  RendererScheduler();
-  DISALLOW_COPY_AND_ASSIGN(RendererScheduler);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_RENDERER_SCHEDULER_RENDERER_SCHEDULER_H_