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

Source/devtools/front_end/timeline/TimelineModel.js

 /*
  * Copyright (C) 2012 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 233 matching lines @@
 
     saveToFile: function()
     {
         throw new Error("Not implemented");
     },
 
     reset: function()
     {
         this._loadedFromFile = false;
         this._records = [];
-        this._minimumRecordTime = -1;
-        this._maximumRecordTime = -1;
+        this._minimumRecordTime = 0;
+        this._maximumRecordTime = 0;
         /** @type {!Array.<!WebInspector.TimelineModel.Record>} */
         this._mainThreadTasks =  [];
         /** @type {!Array.<!WebInspector.TimelineModel.Record>} */
         this._gpuThreadTasks = [];
         /** @type {!Array.<!WebInspector.TimelineModel.Record>} */
         this._eventDividerRecords = [];
         this.dispatchEventToListeners(WebInspector.TimelineModel.Events.RecordsCleared);
     },
 
     /**
@@ skipping 13 matching lines @@
     },
 
     /**
      * @param {!WebInspector.TimelineModel.Record} record
      */
     _updateBoundaries: function(record)
     {
         var startTime = record.startTime();
         var endTime = record.endTime();
 
-        if (this._minimumRecordTime === -1 || startTime < this._minimumRecordTime)
+        if (!this._minimumRecordTime || startTime < this._minimumRecordTime)
             this._minimumRecordTime = startTime;
-        if ((this._maximumRecordTime === -1 && endTime) || endTime > this._maximumRecordTime)
+        if (endTime > this._maximumRecordTime)
             this._maximumRecordTime = endTime;
     },
 
     /**
      * @return {!Array.<!WebInspector.TimelineModel.Record>}
      */
     mainThreadTasks: function()
     {
         return this._mainThreadTasks;
     },
@@ skipping 184 matching lines @@
         function recordTimestampComparator(a, b)
         {
             // Never return 0, as the merge function will squash identical entries.
             return a.startTime() < b.startTime() ? -1 : 1;
         }
         var result = this._backgroundRecordsBuffer.mergeOrdered(records, recordTimestampComparator);
         this._backgroundRecordsBuffer = [];
         return result;
     }
 }