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

Source/devtools/front_end/timeline/TimelinePanel.js

Index: Source/devtools/front_end/timeline/TimelinePanel.js
diff --git a/Source/devtools/front_end/timeline/TimelinePanel.js b/Source/devtools/front_end/timeline/TimelinePanel.js
index c974076e7fe1100608985521116b7e6798067217..3f6521084923e53d3c052d6b59094922077f1eff 100644
--- a/Source/devtools/front_end/timeline/TimelinePanel.js
+++ b/Source/devtools/front_end/timeline/TimelinePanel.js
@@ -204,10 +204,7 @@ WebInspector.TimelinePanel.prototype = {
     {
         if (this._windowStartTime)
             return this._windowStartTime;
-        var minimumRecordTime = this._model.minimumRecordTime();
-        if (minimumRecordTime && minimumRecordTime != -1)
-            return minimumRecordTime;
-        return 0;
+        return this._model.minimumRecordTime();
     },
 
     /**
@@ -217,10 +214,7 @@ WebInspector.TimelinePanel.prototype = {
     {
         if (this._windowEndTime < Infinity)
             return this._windowEndTime;
-        var maximumRecordTime = this._model.maximumRecordTime();
-        if (maximumRecordTime && maximumRecordTime != -1)
-            return maximumRecordTime;
-        return Infinity;
+        return this._model.maximumRecordTime() || Infinity;
     },
 
     /**