Telemetry media Seek action and metrics.

tools/perf/perf_tools/media_metrics.js

-// Copyright 2013 The Chromium Authors. All rights reserved.
+// Copyright (c) 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.
 
 // This file contains common utilities to find video/audio elements on a page
 // and collect metrics for each.
 
 (function() {
   // MediaMetric class responsible for collecting metrics on a media element.
   // It attaches required event listeners in order to collect different metrics.
   function MediaMetricBase(element) {
     checkElementIsNotBound(element);
     this.metrics = {};
     this.id = '';
     this.element = element;
-    // Listen to when a Telemetry 'Play' action gets called.
-    // TODO(shadi): Add event listeners for other media actions here.
-    if (this.element)
-      this.element.addEventListener('willPlay', this.onWillPlay, false);
   }
 
   MediaMetricBase.prototype.getMetrics = function() {
     return this.metrics;
   };
 
   MediaMetricBase.prototype.getSummary = function() {
     return {
       'id': this.id,
       'metrics': this.getMetrics()
     };
   };
 
-  MediaMetricBase.prototype.onWillPlay = function() {
-    this.playbackTimer = new Timer();
-  };
-
   function HTMLMediaMetric(element) {
     MediaMetricBase.prototype.constructor.call(this, element);
     // Set the basic event handlers for HTML5 media element.
     var metric = this;
     function onVideoLoad(event) {
       // If a 'Play' action is performed, then playback_timer != undefined.
       if (metric.playbackTimer == undefined)
         metric.playbackTimer = new Timer();
     }
     // For the cases where autoplay=true, and without a 'play' action, we want
     // to start playbackTimer at 'play' or 'loadedmetadata' events.
     this.element.addEventListener('play', onVideoLoad);
     this.element.addEventListener('loadedmetadata', onVideoLoad);
     this.element.addEventListener('playing', function(e) {
         metric.onPlaying(e);
       });
     this.element.addEventListener('ended', function(e) {
         metric.onEnded(e);
       });
     this.setID();
+
+    // Listen to when a Telemetry actions gets called.
+    this.element.addEventListener('willPlay', function (e) {
+        metric.onWillPlay(e);
+      }, false);
+    this.element.addEventListener('willSeek', function (e) {
+        metric.onWillSeek(e);
+      }, false);
   }
 
   HTMLMediaMetric.prototype = new MediaMetricBase();
   HTMLMediaMetric.prototype.constructor = HTMLMediaMetric;
+
   HTMLMediaMetric.prototype.setID = function() {
     if (this.element.src)
       this.id = this.element.src.substring(this.element.src.lastIndexOf("/")+1);
     else if (this.element.id)
       this.id = this.element.id;
     else
       this.id = 'media_' + window.__globalCounter++;
   };
 
-  HTMLMediaMetric.prototype.getMetrics = function() {
-    this.metrics['decoded_frame_count'] = this.element.webkitDecodedFrameCount;
-    this.metrics['dropped_frame_count'] = this.element.webkitDroppedFrameCount;
-    this.metrics['decoded_video_bytes'] =
-        this.element.webkitVideoDecodedByteCount;
-    this.metrics['decoded_audio_bytes'] =
-        this.element.webkitAudioDecodedByteCount;
-    return this.metrics;
+  HTMLMediaMetric.prototype.onWillPlay = function(e) {
+    this.playbackTimer = new Timer();
   };
 
+  HTMLMediaMetric.prototype.onWillSeek = function(e) {
+    var seekLabel = '';
+    if (e.seekLabel)
+      seekLabel = '_' + e.seekLabel;
+    var metric = this;
+    var onSeeked = function(e) {
+        metric.appendMetric('seek' + seekLabel, metric.seekTimer.stop())
+        e.target.removeEventListener('seeked', onSeeked);
+      };
+    this.seekTimer = new Timer();
+    this.element.addEventListener('seeked', onSeeked);
+  };
+
+  HTMLMediaMetric.prototype.appendMetric = function(metric, value) {
+    if (!this.metrics[metric])
+      this.metrics[metric] = [];
+    this.metrics[metric].push(value);
+  }
+
   HTMLMediaMetric.prototype.onPlaying = function(event) {
     // Playing event can fire more than once if seeking.
     if (!this.metrics['time_to_play'])
       this.metrics['time_to_play'] = this.playbackTimer.stop();
   };
 
   HTMLMediaMetric.prototype.onEnded = function(event) {
     this.metrics['playback_time'] = this.playbackTimer.stop();
   };
 
+  HTMLMediaMetric.prototype.getMetrics = function() {
+    this.metrics['decoded_frame_count'] = this.element.webkitDecodedFrameCount;
+    this.metrics['dropped_frame_count'] = this.element.webkitDroppedFrameCount;
+    this.metrics['decoded_video_bytes'] =
+        this.element.webkitVideoDecodedByteCount;
+    this.metrics['decoded_audio_bytes'] =
+        this.element.webkitAudioDecodedByteCount;
+    return this.metrics;
+  };
+
   function MediaMetric(element) {
     if (element instanceof HTMLMediaElement)
       return new HTMLMediaMetric(element);
     throw new Error('Unrecognized media element type.');
   }
 
   function Timer() {
     this.start_ = 0;
     this.start();
   }
@@ skipping 43 matching lines @@
     for (var i = 0; i < window.__mediaMetrics.length; i++)
       metrics.push(window.__mediaMetrics[i].getSummary());
     return metrics;
   }
 
   window.__globalCounter = 0;
   window.__mediaMetrics = [];
   window.__getAllMetrics = getAllMetrics;
   window.__createMediaMetricsForDocument = createMediaMetricsForDocument;
 })();