[Invalidation Tracking] Include DescendantInvalidationSet id in trace events

Source/core/inspector/InspectorTraceEvents.h

Index: Source/core/inspector/InspectorTraceEvents.h
diff --git a/Source/core/inspector/InspectorTraceEvents.h b/Source/core/inspector/InspectorTraceEvents.h
index d658d9ff08e0c37e8c3fd69fa7df0f65c3dc6016..9f8dcfdb8f07afa0bc14c1f93f5d824f9d816634 100644
--- a/Source/core/inspector/InspectorTraceEvents.h
+++ b/Source/core/inspector/InspectorTraceEvents.h
@@ -45,6 +45,8 @@ public:
     static PassRefPtr<TraceEvent::ConvertableToTraceFormat> data(Node*, const StyleChangeReasonForTracing&);
 };
 
+String descendantInvalidationSetToIdString(const DescendantInvalidationSet&);
+
 class InspectorStyleInvalidatorInvalidateEvent {
 public:
     static const char ElementHasPendingInvalidationList[];