Support counter graphs in Timeline based on trace events

Source/devtools/front_end/timeline/MemoryCountersGraph.js

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 51 matching lines @@
      * @param {!WebInspector.TimelineModel.Record} record
      */
     addRecord: function(record)
     {
         /**
          * @param {!WebInspector.TimelineModel.Record} record
          * @this {!WebInspector.MemoryCountersGraph}
          */
         function addStatistics(record)
         {
-            if (record.type() !== WebInspector.TimelineModel.RecordType.UpdateCounters)
+            var counters = record.counters();
+            if (!counters)
                 return;
-            var counters = record.data();
             for (var name in counters) {
                 var counter = this._countersByName[name];
                 if (counter)
                     counter.appendSample(record.endTime() || record.startTime(), counters[name]);
             }
 
             var gpuMemoryLimitCounterName = "gpuMemoryLimitKB";
             if (this._gpuMemoryCounter && (gpuMemoryLimitCounterName in counters))
                 this._gpuMemoryCounter.setLimit(counters[gpuMemoryLimitCounterName]);
         }
         WebInspector.TimelineModel.forAllRecords([record], null, addStatistics.bind(this));
         this.scheduleRefresh();
     },
 
     refreshRecords: function()
     {
         this.reset();
         var records = this._model.records();
         for (var i = 0; i < records.length; ++i)
             this.addRecord(records[i]);
     },
 
     __proto__: WebInspector.CountersGraph.prototype
 }