Encapsulate implementation-specific timeline record handling in TimelineUIUtils

Source/devtools/front_end/timeline/TimelineMemoryOverview.js

Index: Source/devtools/front_end/timeline/TimelineMemoryOverview.js
diff --git a/Source/devtools/front_end/timeline/TimelineMemoryOverview.js b/Source/devtools/front_end/timeline/TimelineMemoryOverview.js
index 17f2fc0d6c898a6735abe10ab1b1690c58a05e14..f0c1a91f76a7411b0f041e8ad4da8e732669c4b8 100644
--- a/Source/devtools/front_end/timeline/TimelineMemoryOverview.js
+++ b/Source/devtools/front_end/timeline/TimelineMemoryOverview.js
@@ -32,10 +32,12 @@
  * @constructor
  * @extends {WebInspector.TimelineOverviewBase}
  * @param {!WebInspector.TimelineModel} model
+ * @param {!WebInspector.TimelineUIUtils} uiUtils
  */
-WebInspector.TimelineMemoryOverview = function(model)
+WebInspector.TimelineMemoryOverview = function(model, uiUtils)
 {
     WebInspector.TimelineOverviewBase.call(this, model);
+    this._uiUtils = uiUtils;
     this.element.id = "timeline-overview-memory";
 
     this._heapSizeLabel = this.element.createChild("div", "memory-graph-label");
@@ -63,12 +65,13 @@ WebInspector.TimelineMemoryOverview.prototype = {
         var minUsedHeapSize = 100000000000;
         var minTime = this._model.minimumRecordTime();
         var maxTime = this._model.maximumRecordTime();
+        var uiUtils = this._uiUtils;
         /**
          * @param {!WebInspector.TimelineModel.Record} record
          */
         function calculateMinMaxSizes(record)
         {
-            var counters = record.counters();
+            var counters = uiUtils.countersForRecord(record);
             if (!counters || !counters.jsHeapSizeUsed)
                 return;
             maxUsedHeapSize = Math.max(maxUsedHeapSize, counters.jsHeapSizeUsed);
@@ -90,7 +93,7 @@ WebInspector.TimelineMemoryOverview.prototype = {
          */
         function buildHistogram(record)
         {
-            var counters = record.counters();
+            var counters = uiUtils.countersForRecord(record);
             if (!counters || !counters.jsHeapSizeUsed)
                 return;
             var x = Math.round((record.endTime() - minTime) * xFactor);