DevTools: Show JS callstacks on tracing-based timeline

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 e0cdf424bcd916557957b61cbc0099271aaa6578..931ac9ba228c7f362aaad30f5317bb79457c8213 100644
--- a/Source/devtools/front_end/timeline/TracingTimelineUIUtils.js
+++ b/Source/devtools/front_end/timeline/TracingTimelineUIUtils.js
@@ -352,6 +352,10 @@ WebInspector.TracingTimelineUIUtils.buildDetailsNodeForTraceEvent = function(eve
     case recordType.FunctionCall:
         details = linkifyLocation(eventData["scriptId"], eventData["scriptName"], eventData["scriptLine"], 0);
         break;
+    case recordType.JSFrame:
+        details = linkifyLocation(eventData["scriptId"], eventData["url"], eventData["lineNumber"], eventData["columnNumber"]);
+        detailsText = eventData["functionName"];
+        break;
     case recordType.FireAnimationFrame:
         detailsText = eventData["id"];
         break;
@@ -421,7 +425,9 @@ WebInspector.TracingTimelineUIUtils.buildDetailsNodeForTraceEvent = function(eve
         break;
     }
 
-    if (!details && detailsText)
+    if (details && detailsText)
+        details.textContent = detailsText;
+    else if (!details && detailsText)
         details = document.createTextNode(detailsText);
     return details;