Sync HTML element interfaces S-V with the spec

Source/core/events/Event.idl

Index: Source/core/events/Event.idl
diff --git a/Source/core/events/Event.idl b/Source/core/events/Event.idl
index 1838855d32dda648d0c28239a2a301d6a21c9f01..6283320fa24214918a9afc8732a2302acff033e4 100644
--- a/Source/core/events/Event.idl
+++ b/Source/core/events/Event.idl
@@ -52,6 +52,10 @@
                    [Default=Undefined] optional boolean canBubbleArg,
                    [Default=Undefined] optional boolean cancelableArg);
 
+    // Shadow DOM
+    // https://w3c.github.io/webcomponents/spec/shadow/#extensions-to-event-interface
+    [MeasureAs=EventPath] readonly attribute EventTarget[] path;
+
     // Non-standard APIs
     const unsigned short MOUSEDOWN = 1;
     const unsigned short MOUSEUP   = 2;
@@ -72,5 +76,4 @@
     [MeasureAs=EventSrcElement] readonly attribute EventTarget srcElement;
     [MeasureAs=EventReturnValue, CallWith=ExecutionContext, ImplementedAs=legacyReturnValue] attribute boolean returnValue;
     [MeasureAs=EventCancelBubble] attribute boolean cancelBubble;
-    [MeasureAs=EventPath] readonly attribute EventTarget[] path;
 };