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

content/browser/resources/media/timeline_graph_view.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 TimelineGraphView displays a timeline graph on a canvas element.
  */
 var TimelineGraphView = (function() {
   'use strict';
 
@@ skipping 196 matching lines @@
       // Restore original transformation matrix.
       context.restore();
     },
 
     /**
      * Draw time labels below the graph.  Takes in start time as an argument
      * since it may not be |startTime_|, when we're displaying the entire
      * time range.
      */
     drawTimeLabels: function(context, width, height, textHeight, startTime) {
-      // Text for a time string to use in determining how far apart
-      // to place text labels.
-      var sampleText = (new Date(startTime)).toLocaleTimeString();
-
-      // The desired spacing for text labels.
-      var targetSpacing = context.measureText(sampleText).width +
-                              LABEL_LABEL_HORIZONTAL_SPACING;
-
-      // The allowed time step values between adjacent labels.  Anything much
-      // over a couple minutes isn't terribly realistic, given how much memory
-      // we use, and how slow a lot of the net-internals code is.
-      var timeStepValues = [
-        1000,  // 1 second
-        1000 * 5,
-        1000 * 30,
-        1000 * 60,  // 1 minute
-        1000 * 60 * 5,
-        1000 * 60 * 30,
-        1000 * 60 * 60,  // 1 hour
-        1000 * 60 * 60 * 5
-      ];
-
-      // Find smallest time step value that gives us at least |targetSpacing|,
-      // if any.
-      var timeStep = null;
-      for (var i = 0; i < timeStepValues.length; ++i) {
-        if (timeStepValues[i] / DEFAULT_SCALE >= targetSpacing) {
-          timeStep = timeStepValues[i];
-          break;
-        }
-      }
-
-      // If no such value, give up.
-      if (!timeStep)
-        return;
+      // Draw the labels 1 minute apart.
+      var timeStep = 1000 * 60;
 
       // Find the time for the first label.  This time is a perfect multiple of
       // timeStep because of how UTC times work.
       var time = Math.ceil(startTime / timeStep) * timeStep;
 
       context.textBaseline = 'bottom';
       context.textAlign = 'center';
       context.fillStyle = TEXT_COLOR;
       context.strokeStyle = GRID_COLOR;
 
@@ skipping 285 matching lines @@
         for (var i = 1; i < this.labels_.length; ++i)
           context.fillText(this.labels_[i], x, step * i);
       }
     };
 
     return Graph;
   })();
 
   return TimelineGraphView;
 })();