Revert "Delete CC."

cc/debug/lap_timer.h

+// Copyright 2014 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 CC_DEBUG_LAP_TIMER_H_
+#define CC_DEBUG_LAP_TIMER_H_
+
+#include "base/time/time.h"
+
+namespace cc {
+
+// LapTimer is used to calculate average times per "Lap" in perf tests.
+// Current() reports the time since the last call to Start().
+// Store() adds the time since the last call to Start() to the accumulator, and
+// resets the start time to now. Stored() returns the accumulated time.
+// NextLap increments the lap counter, used in counting the per lap averages.
+// If you initialize the LapTimer with a non zero warmup_laps, it will ignore
+// the times for that many laps at the start.
+// If you set the time_limit then you can use HasTimeLimitExpired() to see if
+// the current accumulated time has crossed that threshold, with an optimization
+// that it only tests this every check_interval laps.
+class LapTimer {
+ public:
+  LapTimer(int warmup_laps, base::TimeDelta time_limit, int check_interval);
+  // Resets the timer back to it's starting state.
+  void Reset();
+  // Sets the start point to now.
+  void Start();
+  // Returns true if there are no more warmup laps to do.
+  bool IsWarmedUp();
+  // Advance the lap counter and update the accumulated time.
+  // The accumulated time is only updated every check_interval laps.
+  // If accumulating then the start point will also be updated.
+  void NextLap();
+  // Returns true if the stored time has exceeded the time limit specified.
+  // May cause a call to Store().
+  bool HasTimeLimitExpired();
+  // Returns true if all lap times have been timed. Only true every n'th
+  // lap, where n = check_interval.
+  bool HasTimedAllLaps();
+  // The average milliseconds per lap.
+  float MsPerLap();
+  // The number of laps per second.
+  float LapsPerSecond();
+  // The number of laps recorded.
+  int NumLaps();
+
+ private:
+  base::TimeDelta start_time_;
+  base::TimeDelta accumulator_;
+  int num_laps_;
+  int warmup_laps_;
+  int remaining_warmups_;
+  int remaining_no_check_laps_;
+  base::TimeDelta time_limit_;
+  int check_interval_;
+
+  DISALLOW_COPY_AND_ASSIGN(LapTimer);
+};
+
+}  // namespace cc
+
+#endif  // CC_DEBUG_LAP_TIMER_H_