Initialize min/max record time to 0 instead of -1 or null

Source/devtools/front_end/timeline/TimelineOverviewPane.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 391 matching lines @@
 
     /**
      * @param {number} startTime
      * @param {number} endTime
      * @return {!{left: number, right: number}}
      */
     windowBoundaries: function(startTime, endTime)
     {
         var absoluteMin = this._model.minimumRecordTime();
         var timeSpan = this._model.maximumRecordTime() - absoluteMin;
-        var haveRecords = absoluteMin >= 0;
+        var haveRecords = absoluteMin > 0;
         return {
             left: haveRecords && startTime ? Math.min((startTime - absoluteMin) / timeSpan, 1) : 0,
             right: haveRecords && endTime < Infinity ? (endTime - absoluteMin) / timeSpan : 1
         }
     },
 
     resetCanvas: function()
     {
         this._canvas.width = this.element.clientWidth * window.devicePixelRatio;
         this._canvas.height = this.element.clientHeight * window.devicePixelRatio;
     },
 
     __proto__: WebInspector.VBox.prototype
 }