Fix exception when selecting record in timeline based on trace events

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 421 matching lines @@
     _findAncestorEvent: function(name)
     {
         for (var i = this._eventStack.length - 1; i >= 0; --i) {
             var event = this._eventStack[i];
             if (event.name === name)
                 return event;
         }
         return null;
     },
 
+    /**
+     * @param {!WebInspector.TimelineModel.Record} record
+     * @return {!WebInspector.TracingModel.Event}
+     */
+    traceEventFrom: function(record)
+    {
+        if (!(record instanceof WebInspector.TracingTimelineModel.TraceEventRecord))
+            throw new Error("Illegal argument.");
+        return record._event;
+    },
+
     __proto__: WebInspector.TimelineModel.prototype
 }
 
 /**
  * @constructor
  * @implements {WebInspector.TimelineModel.Record}
  * @param {!WebInspector.TimelineModel} model
  * @param {!WebInspector.TracingModel.Event} traceEvent
  * @param {?WebInspector.TracingTimelineModel.TraceEventRecord} parentRecord
  */
@@ skipping 191 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("|"));
     }
 }