1 files changed, 161 insertions, 0 deletions
diff --git a/tools/perf/perf_tools/smoothness_metrics.js b/tools/perf/perf_tools/smoothness_metrics.js
new file mode 100644
index 0000000..22336fe
--- /dev/null
+++ b/tools/perf/perf_tools/smoothness_metrics.js
@@ -0,0 +1,161 @@
+// Copyright (c) 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.
+
+'use strict';
+
+/**
+ * @fileoverview This file provides the RenderingStats object, used
+ * to characterize rendering smoothness.
+ */
+(function() {
+  var getTimeMs = (function() {
+    if (window.performance)
+      return (performance.now       ||
+              performance.mozNow    ||
+              performance.msNow     ||
+              performance.oNow      ||
+              performance.webkitNow).bind(window.performance);
+    else
+      return function() { return new Date().getTime(); };
+  })();
+
+  var requestAnimationFrame = (function() {
+    return window.requestAnimationFrame       ||
+           window.webkitRequestAnimationFrame ||
+           window.mozRequestAnimationFrame    ||
+           window.oRequestAnimationFrame      ||
+           window.msRequestAnimationFrame     ||
+           function(callback) {
+             window.setTimeout(callback, 1000 / 60);
+           };
+  })().bind(window);
+
+  /**
+   * Tracks rendering performance using the gpuBenchmarking.renderingStats API.
+   * @constructor
+   */
+  function GpuBenchmarkingRenderingStats() {
+  }
+
+  GpuBenchmarkingRenderingStats.prototype.start = function() {
+    this.startTime_ = getTimeMs();
+    this.initialStats_ = this.getRenderingStats_();
+  }
+
+  GpuBenchmarkingRenderingStats.prototype.stop = function() {
+    this.stopTime_ = getTimeMs();
+    this.finalStats_ = this.getRenderingStats_();
+  }
+
+  GpuBenchmarkingRenderingStats.prototype.getStartValues = function() {
+    if (!this.initialStats_)
+      throw new Error('Start not called.');
+
+    if (!this.finalStats_)
+      throw new Error('Stop was not called.');
+
+    return this.initialStats_;
+  }
+
+  GpuBenchmarkingRenderingStats.prototype.getEndValues = function() {
+    if (!this.initialStats_)
+      throw new Error('Start not called.');
+
+    if (!this.finalStats_)
+      throw new Error('Stop was not called.');
+
+    return this.finalStats_;
+  }
+
+  GpuBenchmarkingRenderingStats.prototype.getDeltas = function() {
+    if (!this.initialStats_)
+      throw new Error('Start not called.');
+
+    if (!this.finalStats_)
+      throw new Error('Stop was not called.');
+
+    var stats = {}
+    for (var key in this.finalStats_)
+      stats[key] = this.finalStats_[key] - this.initialStats_[key];
+    return stats;
+  };
+
+  GpuBenchmarkingRenderingStats.prototype.getRenderingStats_ = function() {
+    var stats = chrome.gpuBenchmarking.renderingStats();
+    stats.totalTimeInSeconds = getTimeMs() / 1000;
+    return stats;
+  };
+
+  /**
+   * Tracks rendering performance using requestAnimationFrame.
+   * @constructor
+   */
+  function RafRenderingStats() {
+    this.recording_ = false;
+    this.frameTimes_ = [];
+  }
+
+  RafRenderingStats.prototype.start = function() {
+    if (this.recording_)
+      throw new Error('Already started.');
+    this.recording_ = true;
+    requestAnimationFrame(this.recordFrameTime_.bind(this));
+  }
+
+  RafRenderingStats.prototype.stop = function() {
+    this.recording_ = false;
+  }
+
+  RafRenderingStats.prototype.getStartValues = function() {
+    var results = {};
+    results.numAnimationFrames = 0;
+    results.numFramesSentToScreen = 0;
+    results.droppedFrameCount = 0;
+    return results;
+  }
+
+  RafRenderingStats.prototype.getEndValues = function() {
+    var results = {};
+    results.numAnimationFrames = this.frameTimes_.length - 1;
+    results.numFramesSentToScreen = results.numAnimationFrames;
+    results.droppedFrameCount = this.getDroppedFrameCount_(this.frameTimes_);
+    return results;
+  }
+
+  RafRenderingStats.prototype.getDeltas = function() {
+    var endValues = this.getEndValues();
+    endValues.totalTimeInSeconds = (
+        this.frameTimes_[this.frameTimes_.length - 1] -
+        this.frameTimes_[0]) / 1000;
+    return endValues;
+  };
+
+  RafRenderingStats.prototype.recordFrameTime_ = function(timestamp) {
+    if (!this.recording_)
+      return;
+
+    this.frameTimes_.push(timestamp);
+    requestAnimationFrame(this.recordFrameTime_.bind(this));
+  };
+
+  RafRenderingStats.prototype.getDroppedFrameCount_ = function(frameTimes) {
+    var droppedFrameCount = 0;
+    for (var i = 1; i < frameTimes.length; i++) {
+      var frameTime = frameTimes[i] - frameTimes[i-1];
+      if (frameTime > 1000 / 55)
+        droppedFrameCount++;
+    }
+    return droppedFrameCount;
+  };
+
+  function RenderingStats() {
+    if (window.chrome && chrome.gpuBenchmarking &&
+        chrome.gpuBenchmarking.renderingStats) {
+      return new GpuBenchmarkingRenderingStats();
+    }
+    return new RafRenderingStats();
+  }
+
+  window.__RenderingStats = RenderingStats;
+})();