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

Source/devtools/front_end/timeline/TimelineView.js

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  * Copyright (C) 2012 Intel 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.
@@ skipping 230 matching lines @@
     {
         this._closeRecordDetails();
         this._graphRowsElementWidth = this._graphRowsElement.offsetWidth;
         this._headerElement.style.left = sidebarWidth + "px";
         this._headerElement.style.width = this._itemsGraphsElement.offsetWidth + "px";
         this._scheduleRefresh(false, true);
     },
 
     _resetView: function()
     {
-        this._windowStartTime = -1;
-        this._windowEndTime = -1;
+        this._windowStartTime = 0;
+        this._windowEndTime = 0;
         this._boundariesAreValid = false;
         this._adjustScrollPosition(0);
         this._linkifier.reset();
         this._closeRecordDetails();
         this._automaticallySizeWindow = true;
         this._presentationModel.reset();
     },
 
 
     /**
@@ skipping 186 matching lines @@
                 this._refreshTimeout = setTimeout(this._refresh.bind(this), 300);
         }
     },
 
     _refresh: function()
     {
         if (this._refreshTimeout) {
             clearTimeout(this._refreshTimeout);
             delete this._refreshTimeout;
         }
-        var windowStartTime = this._windowStartTime;
-        var windowEndTime = this._windowEndTime;
+        var windowStartTime = this._windowStartTime || this._model.minimumRecordTime();
+        var windowEndTime = this._windowEndTime || this._model.maximumRecordTime();
         this._timelinePaddingLeft = this._expandOffset;
-        if (windowStartTime === -1)
-            windowStartTime = this._model.minimumRecordTime();
-        if (windowEndTime === -1)
-            windowEndTime = this._model.maximumRecordTime();
         this._calculator.setWindow(windowStartTime, windowEndTime);
         this._calculator.setDisplayWindow(this._timelinePaddingLeft, this._graphRowsElementWidth);
 
         this._refreshRecords();
         if (!this._boundariesAreValid) {
             this._updateEventDividers();
             if (this._frameContainer)
                 this._frameContainer.remove();
             if (this._frameModel) {
                 var frames = this._frameModel.filteredFrames(windowStartTime, windowEndTime);
@@ skipping 827 matching lines @@
             this._element.classList.remove("hidden");
         } else
             this._element.classList.add("hidden");
     },
 
     _dispose: function()
     {
         this._element.remove();
     }
 }