Correctly calculate highlighted quad for tracing based timeline events

Source/devtools/front_end/timeline/TracingTimelineModel.js

Index: Source/devtools/front_end/timeline/TracingTimelineModel.js
diff --git a/Source/devtools/front_end/timeline/TracingTimelineModel.js b/Source/devtools/front_end/timeline/TracingTimelineModel.js
index be87ef4653700ad655d5a96f2f5dda22d125b718..85baefa30e51d4d30541807dd8c18f8b8751dc8e 100644
--- a/Source/devtools/front_end/timeline/TracingTimelineModel.js
+++ b/Source/devtools/front_end/timeline/TracingTimelineModel.js
@@ -366,6 +366,7 @@ WebInspector.TracingTimelineModel.prototype = {
             var frameId = event.args["beginData"]["frame"];
             event.initiator = this._layoutInvalidate[frameId];
             event.backendNodeId = event.args["endData"]["rootNode"];
+            event.clip =  event.args["endData"]["root"];

[caseq, 2014/06/10 13:21:23]

I'd rather not use clip, this seems to be not generic enough and particularly
sounds weird in case of layout. How about just _highlightQuad?

[yurys, 2014/06/10 13:25:37]

Done.

             this._layoutInvalidate[frameId] = null;
             if (this._currentScriptEvent)
                 event.warning = WebInspector.UIString("Forced synchronous layout is a possible performance bottleneck.");
@@ -392,6 +393,8 @@ WebInspector.TracingTimelineModel.prototype = {
             break;
 
         case recordTypes.Paint:
+            event.clip = event.args["data"]["clip"];
+            // Initionally fall through.
         case recordTypes.ScrollLayer:
             event.backendNodeId = event.args["data"]["nodeId"];
             break;
@@ -581,6 +584,14 @@ WebInspector.TracingTimelineModel.TraceEventRecord.prototype = {
     },
 
     /**
+     * @return {?Object}
+     */
+    highlightQuad: function()
+    {
+        return this._event.clip || null;
+    },
+
+    /**
      * @return {string}
      */
     frameId: function()