DevTools: log worker thread ids on the main thread when Timeline recording is enabled

LayoutTests/inspector/tracing/worker-events.html

Index: LayoutTests/inspector/tracing/worker-events.html
diff --git a/LayoutTests/inspector/tracing/worker-events.html b/LayoutTests/inspector/tracing/worker-events.html
index 921fc01c6ef48320797d0cb3c8da70097c76bef9..72901a27b20d3ca12db201455b74c3d4b060add6 100644
--- a/LayoutTests/inspector/tracing/worker-events.html
+++ b/LayoutTests/inspector/tracing/worker-events.html
@@ -51,11 +51,11 @@ function test()
 
     function processEvent(event)
     {
-        if (event.category !== WebInspector.TracingModel.DevToolsMetadataEventCategory || event.name !== WebInspector.TracingModel.DevToolsMetadataEvent.TracingStartedInWorker)
+        if (event.category !== WebInspector.TracingModel.DevToolsMetadataEventCategory || event.name !== WebInspector.TracingModel.DevToolsMetadataEvent.TracingSessionIdForWorker)
             return;
 
         ++workerMetadataEventCount;
-        InspectorTest.assertEquals(InspectorTest.tracingModel.sessionId(), event.args["sessionId"]);
+        InspectorTest.assertEquals(InspectorTest.tracingModel.sessionId(), event.args["data"]["sessionId"]);
         InspectorTest.addResult("Got DevTools worker metadata event(" + workerMetadataEventCount +  "): " + event.name);
     }