Update the FIXME around event handler attributes on body/frameset

Source/core/html/HTMLFrameSetElement.idl

Index: Source/core/html/HTMLFrameSetElement.idl
diff --git a/Source/core/html/HTMLFrameSetElement.idl b/Source/core/html/HTMLFrameSetElement.idl
index e7d42b9c4ce740a15544f4226408731d9c17f16a..21caf79c3c14206c5336e1b17a69d8588a3439a8 100644
--- a/Source/core/html/HTMLFrameSetElement.idl
+++ b/Source/core/html/HTMLFrameSetElement.idl
@@ -27,9 +27,9 @@
     [Reflect] attribute DOMString cols;
     [Reflect] attribute DOMString rows;
 
-    // FIXME: The spec requires special behavior for these event
-    // handler attributes but does not include them in the IDL:
-    // https://www.w3.org/Bugs/Public/show_bug.cgi?id=28166
+    // TODO(philipj): These event handler attributes should be inherited from
+    // HTMLElement (which implements GlobalEventHandlers), but have different
+    // behavior. See https://www.w3.org/Bugs/Public/show_bug.cgi?id=28166
     attribute EventHandler onblur;
     attribute EventHandler onerror;
     attribute EventHandler onfocus;