Revert "reland of Improve linearized pdf load/show time."

pdf/timer.h

-// Copyright 2016 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 PDF_TIMER_H_
-#define PDF_TIMER_H_
-
-#include "base/macros.h"
-#include "ppapi/utility/completion_callback_factory.h"
-
-namespace chrome_pdf {
-
-// Timer implementation for pepper plugins, based on pp::Core::CallOnMainThread.
-// We can not use base::Timer for plugins, because they have no
-// base::MessageLoop, on which it is based.
-class Timer {
- public:
-  explicit Timer(int delay_in_milliseconds);
-  virtual ~Timer();
-
-  virtual void OnTimer() = 0;
-
- private:
-  void PostCallback();
-  void TimerProc(int32_t result);
-
-  int delay_;
-  pp::CompletionCallbackFactory<Timer> callback_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(Timer);
-};
-
-}  // namespace chrome_pdf
-
-#endif  // PDF_TIMER_H_