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

Source/core/inspector/InspectorTraceEvents.cpp

Index: Source/core/inspector/InspectorTraceEvents.cpp
diff --git a/Source/core/inspector/InspectorTraceEvents.cpp b/Source/core/inspector/InspectorTraceEvents.cpp
index efa66df4ba0e0292bf335bf5b7cca04896f62fb0..2fd955c2b74ecf3b5bfb45d8aa165dcf85aba0cf 100644
--- a/Source/core/inspector/InspectorTraceEvents.cpp
+++ b/Source/core/inspector/InspectorTraceEvents.cpp
@@ -17,6 +17,7 @@
 #include "core/page/Page.h"
 #include "core/rendering/RenderImage.h"
 #include "core/rendering/RenderObject.h"
+#include "core/workers/WorkerThread.h"
 #include "core/xml/XMLHttpRequest.h"
 #include "platform/JSONValues.h"
 #include "platform/TracedValue.h"
@@ -355,4 +356,12 @@ PassRefPtr<TraceEvent::ConvertableToTraceFormat> InspectorTimeStampEvent::data(E
     return value;
 }
 
+PassRefPtr<TraceEvent::ConvertableToTraceFormat> InspectorTracingSessionIdForWorkerEvent::data(const String& sessionId, WorkerThread* workerThread)
+{
+    RefPtr<TracedValue> value = TracedValue::create();
+    value->setString("sessionId", sessionId);
+    value->setDouble("workerThreadId", workerThread->platformThreadId());
+    return value;
+}
+
 }