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

Source/devtools/front_end/timeline/TracingTimelineModel.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @param {!WebInspector.TracingModel} tracingModel
  * @constructor
  * @extends {WebInspector.TimelineModel}
  */
 WebInspector.TracingTimelineModel = function(tracingModel)
@@ skipping 151 matching lines @@
         }
         this._resetProcessingState();
 
         this._inspectedTargetEvents.sort(WebInspector.TracingModel.Event.compareStartTime);
 
         this._buildTimelineRecords();
         this.dispatchEventToListeners(WebInspector.TimelineModel.Events.RecordingStopped);
     },
 
     /**
-     * @return {?number}
+     * @return {number}
      */
     minimumRecordTime: function()
     {
         return this._tracingModel.minimumRecordTime();
     },
 
     /**
-     * @return {?number}
+     * @return {number}
      */
     maximumRecordTime: function()
     {
         return this._tracingModel.maximumRecordTime();
     },
 
     /**
      * @return {!Array.<!WebInspector.TracingModel.Event>}
      */
     inspectedTargetEvents: function()
@@ skipping 451 matching lines @@
     {
         var tokens = [this.title()];
         var data = this._event.args.data;
         if (data) {
             for (var key in data)
                 tokens.push(data[key]);
         }
         return regExp.test(tokens.join("|"));
     }
 }