Use TimelineUIUtils to create BeginFrame divider

Source/devtools/front_end/timeline/TracingTimelineUIUtils.js

Index: Source/devtools/front_end/timeline/TracingTimelineUIUtils.js
diff --git a/Source/devtools/front_end/timeline/TracingTimelineUIUtils.js b/Source/devtools/front_end/timeline/TracingTimelineUIUtils.js
index 56244d1683be379d366b49f4473a1fdf50803844..725f9b1c27f3e378d3d64533ed2788266ad4d8fc 100644
--- a/Source/devtools/front_end/timeline/TracingTimelineUIUtils.js
+++ b/Source/devtools/front_end/timeline/TracingTimelineUIUtils.js
@@ -102,6 +102,14 @@ WebInspector.TracingTimelineUIUtils.prototype = {
     },
 
     /**
+     * @return {!Element}
+     */
+    createBeginFrameDivider: function()
+    {
+        return this.createEventDivider(WebInspector.TracingTimelineModel.RecordType.BeginFrame);
+    },
+
+    /**
      * @param {string} recordType
      * @param {string=} title
      * @return {!Element}