Revert 199008 "Fixes a memory leak when running webrtc-internals..."

trunk/src/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) {
-      // Draw the labels 1 minute apart.
-      var timeStep = 1000 * 60;
+      // 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;
 
       // 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;
 })();