DevTools: encapsulate presentation model in timeline view.

Source/devtools/front_end/TimelineFrameModel.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 184 matching lines @@
      */
     _startBackgroundFrame: function(record)
     {
         if (!this._hasThreadedCompositing) {
             this._lastFrame = null;
             this._hasThreadedCompositing = true;
         }
         if (this._lastFrame)
             this._flushFrame(this._lastFrame, record);
 
-        this._lastFrame = new WebInspector.TimelineFrame(this, record);
+        this._lastFrame = new WebInspector.TimelineFrame(record);
     },
 
     /**
      * @param {!WebInspector.TimelineModel.Record} record
      */
     _startMainThreadFrame: function(record)
     {
         if (this._lastFrame)
             this._flushFrame(this._lastFrame, record);
-        this._lastFrame = new WebInspector.TimelineFrame(this, record);
+        this._lastFrame = new WebInspector.TimelineFrame(record);
     },
 
     /**
      * @param {!WebInspector.TimelineFrame} frame
      * @param {!Object} record
      */
     _flushFrame: function(frame, record)
     {
         frame._setEndTime(record.startTime);
         this._frames.push(frame);
@@ skipping 46 matching lines @@
         this.maxDuration = Math.max(this.maxDuration, duration);
         WebInspector.TimelineUIUtils.aggregateTimeByCategory(this.timeByCategory, frames[i].timeByCategory);
     }
     this.average = totalDuration / this.frameCount;
     var variance = sumOfSquares / this.frameCount - this.average * this.average;
     this.stddev = Math.sqrt(variance);
 }
 
 /**
  * @constructor
- * @param {!WebInspector.TimelineFrameModel} model
  * @param {!Object} record
  */
-WebInspector.TimelineFrame = function(model, record)
+WebInspector.TimelineFrame = function(record)
 {
     this.startTime = record.startTime;
-    this.startTimeOffset = model._model.recordOffsetInMillis(record);
+    this.startTimeOffset = record.startTimeOffset;
     this.endTime = this.startTime;
     this.duration = 0;
     this.timeByCategory = {};
     this.cpuTime = 0;
 }
 
 WebInspector.TimelineFrame.prototype = {
     /**
      * @param {number} endTime
      */
@@ skipping 23 matching lines @@
         this._updateCpuTime();
     },
 
     _updateCpuTime: function()
     {
         this.cpuTime = 0;
         for (var key in this.timeByCategory)
             this.cpuTime += this.timeByCategory[key];
     }
 }