Update from https://crrev.com/303153

cc/debug/paint_time_counter.cc

 // Copyright 2012 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.
 
 #include "cc/debug/paint_time_counter.h"
 
 namespace cc {
 
 // static
 scoped_ptr<PaintTimeCounter> PaintTimeCounter::Create() {
   return make_scoped_ptr(new PaintTimeCounter());
 }
 
-PaintTimeCounter::PaintTimeCounter()
-  : can_save_paint_time_delta_(false) {
+PaintTimeCounter::PaintTimeCounter() {
 }
 
-void PaintTimeCounter::SavePaintTime(const base::TimeDelta& total_paint_time) {
-  if (can_save_paint_time_delta_) {
-    base::TimeDelta paint_time = total_paint_time - last_total_paint_time_;
-    ring_buffer_.SaveToBuffer(paint_time);
-  }
-
-  last_total_paint_time_ = total_paint_time;
-  can_save_paint_time_delta_ = true;
+void PaintTimeCounter::SavePaintTime(const base::TimeDelta& paint_time) {
+  ring_buffer_.SaveToBuffer(paint_time);
 }
 
 void PaintTimeCounter::GetMinAndMaxPaintTime(base::TimeDelta* min,
                                              base::TimeDelta* max) const {
   *min = base::TimeDelta::FromDays(1);
   *max = base::TimeDelta();
 
   for (RingBufferType::Iterator it = ring_buffer_.Begin(); it; ++it) {
     const base::TimeDelta paint_time = **it;
 
     if (paint_time < *min)
       *min = paint_time;
     if (paint_time > *max)
       *max = paint_time;
   }
 
   if (*min > *max)
     *min = *max;
 }
 
 void PaintTimeCounter::ClearHistory() {
   ring_buffer_.Clear();
-  can_save_paint_time_delta_ = false;
 }
 
 }  // namespace cc