Fixes a memory leak when running webrtc-internals for a long time, by using a circular buffer of si…

content/browser/resources/media/data_series.js

 // 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.
 
 /**
  * A TimelineDataSeries collects an ordered series of (time, value) pairs,
  * and converts them to graph points.  It also keeps track of its color and
  * current visibility state.
+ * It keeps MAX_STATS_DATA_POINT_BUFFER_SIZE data points at most. Old data
+ * points will be dropped when it reaches this size.
  */
 var TimelineDataSeries = (function() {
   'use strict';
 
   /**
    * @constructor
    */
   function TimelineDataSeries() {
     // List of DataPoints in chronological order.
     this.dataPoints_ = [];
 
     // Default color.  Should always be overridden prior to display.
     this.color_ = 'red';
     // Whether or not the data series should be drawn.
     this.isVisible_ = true;
 
     this.cacheStartTime_ = null;
     this.cacheStepSize_ = 0;
     this.cacheValues_ = [];
   }
 
   TimelineDataSeries.prototype = {
     /**
      * Adds a DataPoint to |this| with the specified time and value.
      * DataPoints are assumed to be received in chronological order.
      */
     addPoint: function(timeTicks, value) {
       var time = new Date(timeTicks);
       this.dataPoints_.push(new DataPoint(time, value));
+
+      if (this.dataPoints_.length > MAX_STATS_DATA_POINT_BUFFER_SIZE)
+        this.dataPoints_.shift();
     },
 
     isVisible: function() {
       return this.isVisible_;
     },
 
     show: function(isVisible) {
       this.isVisible_ = isVisible;
     },
 
@@ skipping 52 matching lines @@
    * milliseconds since the Unix epoch, and a numeric value.
    * @constructor
    */
   function DataPoint(time, value) {
     this.time = time;
     this.value = value;
   }
 
   return TimelineDataSeries;
 })();