scheduler: Move the Blink scheduler into Blink

components/scheduler/renderer/task_cost_estimator.cc

-// 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.
-
-#include "components/scheduler/renderer/task_cost_estimator.h"
-
-#include "base/time/default_tick_clock.h"
-
-namespace scheduler {
-
-TaskCostEstimator::TaskCostEstimator(base::TickClock* time_source,
-                                     int sample_count,
-                                     double estimation_percentile)
-    : rolling_time_delta_history_(sample_count),
-      time_source_(time_source),
-      outstanding_task_count_(0),
-      estimation_percentile_(estimation_percentile) {}
-
-TaskCostEstimator::~TaskCostEstimator() {}
-
-void TaskCostEstimator::WillProcessTask(const base::PendingTask& pending_task) {
-  // Avoid measuring the duration in nested run loops.
-  if (++outstanding_task_count_ == 1)
-    task_start_time_ = time_source_->NowTicks();
-}
-
-void TaskCostEstimator::DidProcessTask(const base::PendingTask& pending_task) {
-  if (--outstanding_task_count_ == 0) {
-    base::TimeDelta duration = time_source_->NowTicks() - task_start_time_;
-    rolling_time_delta_history_.InsertSample(duration);
-  }
-}
-
-base::TimeDelta TaskCostEstimator::expected_task_duration() const {
-  return rolling_time_delta_history_.Percentile(estimation_percentile_);
-}
-
-void TaskCostEstimator::Clear() {
-  rolling_time_delta_history_.Clear();
-  expected_task_duration_ = base::TimeDelta();
-}
-
-}  // namespace scheduler