[cssom] Make MediaList and StyleSheetList [NoInterfaceObject]. Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=28518

Author: zcorpan

cssom/Overview.bs

@@ -461,7 +461,8 @@ The {{MediaList}} Interface {#the-medialist-interface}
 
 An object that implements the <code>MediaList</code> interface has an associated <dfn export for=MediaList>collection of media queries</dfn>.
 
-<pre class=idl>[ArrayClass]
+<pre class=idl>[NoInterfaceObject,
+ ArrayClass]
 interface MediaList {
   [TreatNullAs=EmptyString] stringifier attribute DOMString mediaText;
   readonly attribute unsigned long length;
@@ -1087,7 +1088,8 @@ value of the header.
 
 The {{StyleSheetList}} interface represents an ordered collection of <a>CSS style sheets</a>.
 
-<pre class=idl>[ArrayClass]
+<pre class=idl>[NoInterfaceObject,
+ ArrayClass]
 interface StyleSheetList {
   getter StyleSheet? item(unsigned long index);
   readonly attribute unsigned long length;