More about:gpu tracing improvements.

chrome/browser/resources/gpu_internals/timeline_model.js

 // Copyright (c) 2011 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.
 
 
 /**
  * @fileoverview TimelineModel is a parsed representation of the
  * TraceEvents obtained from base/trace_event in which the begin-end
  * tokens are converted into a hierarchy of processes, threads,
  * subrows, and slices.
@@ skipping 91 matching lines @@
 
   /**
    * Builds a model from an array of TraceEvent objects.
    * @param {Array} events An array of TraceEvents created by
    *     TraceEvent.ToJSON().
    * @constructor
    */
   function TimelineModel(events) {
     this.processes = {};
 
-    this.importEvents(events);
+    if (events)
+      this.importEvents(events);
   }
 
   TimelineModel.prototype = {
     __proto__: cr.EventTarget.prototype,
 
     getProcess: function(pid) {
       if (!this.processes[pid])
         this.processes[pid] = new TimelineProcess(pid);
       return this.processes[pid];
     },
@@ skipping 120 matching lines @@
 
   };
 
   return {
     TimelineSlice: TimelineSlice,
     TimelineThread: TimelineThread,
     TimelineProcess: TimelineProcess,
     TimelineModel: TimelineModel
   };
 });