cc: Abstract out proxy timing history

cc/trees/proxy_timing_history.cc

+// Copyright 2013 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/trees/proxy_timing_history.h"
+
+const size_t kDurationHistorySize = 60;
+const double kCommitAndActivationDurationEstimationPercentile = 50.0;
+const double kDrawDurationEstimationPercentile = 100.0;
+const int kDrawDurationEstimatePaddingInMicroseconds = 0;
+
+namespace cc {
+
+ProxyTimingHistory::ProxyTimingHistory()
+    : draw_duration_history_(kDurationHistorySize),
+      begin_main_frame_to_commit_duration_history_(kDurationHistorySize),
+      commit_to_activate_duration_history_(kDurationHistorySize) {}
+
+ProxyTimingHistory::~ProxyTimingHistory() {}
+
+base::TimeDelta ProxyTimingHistory::DrawDurationEstimate() const {
+  base::TimeDelta historical_estimate =
+      draw_duration_history_.Percentile(kDrawDurationEstimationPercentile);
+  base::TimeDelta padding = base::TimeDelta::FromMicroseconds(
+      kDrawDurationEstimatePaddingInMicroseconds);
+  return historical_estimate + padding;
+}
+
+base::TimeDelta ProxyTimingHistory::BeginMainFrameToCommitDurationEstimate()
+    const {
+  return begin_main_frame_to_commit_duration_history_.Percentile(
+      kCommitAndActivationDurationEstimationPercentile);
+}
+
+base::TimeDelta ProxyTimingHistory::CommitToActivateDurationEstimate() const {
+  return commit_to_activate_duration_history_.Percentile(
+      kCommitAndActivationDurationEstimationPercentile);
+}
+
+void ProxyTimingHistory::DidBeginMainFrame() {
+  begin_main_frame_sent_time_ = base::TimeTicks::HighResNow();
+}
+
+void ProxyTimingHistory::DidCommit() {
+  commit_complete_time_ = base::TimeTicks::HighResNow();
+  begin_main_frame_to_commit_duration_history_.InsertSample(
+      commit_complete_time_ - begin_main_frame_sent_time_);
+}
+
+void ProxyTimingHistory::DidActivatePendingTree() {
+  commit_to_activate_duration_history_.InsertSample(
+      base::TimeTicks::HighResNow() - commit_complete_time_);
+}
+
+void ProxyTimingHistory::DidStartDrawing() {
+  start_draw_time_ = base::TimeTicks::HighResNow();
+}
+
+base::TimeDelta ProxyTimingHistory::DidFinishDrawing() {
+  base::TimeDelta draw_duration =
+      base::TimeTicks::HighResNow() - start_draw_time_;
+  draw_duration_history_.InsertSample(draw_duration);
+  return draw_duration;
+}
+
+}  // namespace cc