Revert of Throttle resource message requests during user interaction

content/renderer/scheduler/resource_dispatch_throttler.h

-// Copyright 2015 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_RESOURCE_DISPATCH_THROTTLER_H_
-#define CONTENT_RENDERER_SCHEDULER_RESOURCE_DISPATCH_THROTTLER_H_
-
-#include <deque>
-
-#include "base/threading/thread_checker.h"
-#include "base/time/time.h"
-#include "base/timer/timer.h"
-#include "content/common/content_export.h"
-#include "ipc/ipc_sender.h"
-
-namespace content {
-
-class RendererScheduler;
-
-// Utility class for throttling a stream of resource requests targetted to a
-// specific IPC sender. The throttling itself is very basic:
-//  * When there is no high-priority work imminent to the main thread, as
-//    indicated by the RendererScheduler, throttling is disabled.
-//  * When >= N requests have been sent in a given time window, requests are
-//    throttled. A timer periodically flushes a portion of the queued requests
-//    until all such requests have been flushed.
-// TODO(jdduke): Remove this class after resource requests become sufficiently
-// cheap on the IO thread, crbug.com/440037.
-class CONTENT_EXPORT ResourceDispatchThrottler : public IPC::Sender {
- public:
-  // |flush_period| and |max_requests_per_flush| must be strictly positive
-  // in duration/value.
-  ResourceDispatchThrottler(IPC::Sender* proxied_sender,
-                            RendererScheduler* scheduler,
-                            base::TimeDelta flush_period,
-                            uint32 max_requests_per_flush);
-  ~ResourceDispatchThrottler() override;
-
-  // IPC::Sender implementation:
-  bool Send(IPC::Message* msg) override;
-
- private:
-  friend class ResourceDispatchThrottlerForTest;
-
-  // Virtual for testing.
-  virtual base::TimeTicks Now() const;
-  virtual void ScheduleFlush();
-
-  void Flush();
-  void FlushAll();
-  bool ForwardMessage(IPC::Message* msg);
-
-  base::ThreadChecker thread_checker_;
-
-  IPC::Sender* const proxied_sender_;
-  RendererScheduler* const scheduler_;
-  const base::TimeDelta flush_period_;
-  const uint32 max_requests_per_flush_;
-
-  base::Timer flush_timer_;
-  base::TimeTicks last_sent_request_time_;
-  uint32 sent_requests_since_last_flush_;
-  std::deque<IPC::Message*> throttled_messages_;
-
-  DISALLOW_COPY_AND_ASSIGN(ResourceDispatchThrottler);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_RENDERER_SCHEDULER_RESOURCE_DISPATCH_THROTTLER_H_