Use TimelineUIUtils to create BeginFrame divider

Source/devtools/front_end/timeline/TimelineUIUtils.js

Index: Source/devtools/front_end/timeline/TimelineUIUtils.js
diff --git a/Source/devtools/front_end/timeline/TimelineUIUtils.js b/Source/devtools/front_end/timeline/TimelineUIUtils.js
index 934e679d410ebcaf61f67edd08c15022b7065703..2983f59d77093c0ad8058d78052d53d64f3d92f2 100644
--- a/Source/devtools/front_end/timeline/TimelineUIUtils.js
+++ b/Source/devtools/front_end/timeline/TimelineUIUtils.js
@@ -113,6 +113,13 @@ WebInspector.TimelineUIUtils.prototype = {
         throw new Error("Not implemented.");
     },
     /**
+     * @return {!Element}
+     */
+    createBeginFrameDivider: function()
+    {
+        throw new Error("Not implemented.");
+    },
+    /**
      * @param {string} recordType
      * @param {string=} title
      * @return {!Element}