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

Source/devtools/front_end/timeline/TimelineModel.js

Index: Source/devtools/front_end/timeline/TimelineModel.js
diff --git a/Source/devtools/front_end/timeline/TimelineModel.js b/Source/devtools/front_end/timeline/TimelineModel.js
index 35ebfb508f4abf7979b4da5c3ed17af72e566416..fff19051316d374f012abfda5db9974edbbed773 100644
--- a/Source/devtools/front_end/timeline/TimelineModel.js
+++ b/Source/devtools/front_end/timeline/TimelineModel.js
@@ -251,8 +251,8 @@ WebInspector.TimelineModel.prototype = {
     {
         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>} */
@@ -286,9 +286,9 @@ WebInspector.TimelineModel.prototype = {
         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 ((!this._maximumRecordTime && endTime) || endTime > this._maximumRecordTime)

[alph, 2014/06/09 09:31:14]

Looks like you can drop the part before ||

[yurys, 2014/06/09 09:46:08]

endTime may be undefined and we may end up comparing undefined with something
(which is allowed but not that obvious).

[alph, 2014/06/09 10:09:19]

According to
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...
it shouldn't be undefined.

[yurys, 2014/06/09 11:16:36]

You're right. I confused that with TracingModel.Event.endTime, will update this
change.

             this._maximumRecordTime = endTime;
     },