IDL: make optional arguments (without default) explicit sometimes

Source/core/dom/shadow/ShadowRoot.idl

Index: Source/core/dom/shadow/ShadowRoot.idl
diff --git a/Source/core/dom/shadow/ShadowRoot.idl b/Source/core/dom/shadow/ShadowRoot.idl
index f884756a4f942ac4d426364c6fa72ec529ff9334..f67a06f20f83216820191510d632637dac7316d6 100644
--- a/Source/core/dom/shadow/ShadowRoot.idl
+++ b/Source/core/dom/shadow/ShadowRoot.idl
@@ -31,16 +31,16 @@ interface ShadowRoot : DocumentFragment {
 
     [TreatNullAs=NullString, CustomElementCallbacks, RaisesException=Setter] attribute DOMString innerHTML;
 
-    [RaisesException] Node cloneNode([Default=Undefined] optional boolean deep);
+    [RaisesException] Node cloneNode(optional boolean deep);
     Selection getSelection();
-    Element getElementById([Default=Undefined] optional DOMString elementId);
-    HTMLCollection getElementsByClassName([Default=Undefined] optional DOMString className);
-    HTMLCollection getElementsByTagName([Default=Undefined] optional DOMString tagName);
-    HTMLCollection getElementsByTagNameNS([Default=Undefined] optional DOMString? namespaceURI,
-                                          [Default=Undefined] optional DOMString localName);
+    Element getElementById(optional DOMString elementId);
+    HTMLCollection getElementsByClassName(optional DOMString className);
+    HTMLCollection getElementsByTagName(optional DOMString tagName);
+    HTMLCollection getElementsByTagNameNS(optional DOMString? namespaceURI,
+                                          optional DOMString localName);
 
-    Element elementFromPoint([Default=Undefined] optional long x,
-                             [Default=Undefined] optional long y);
+    Element elementFromPoint(optional long x,
+                             optional long y);
 
     readonly attribute StyleSheetList styleSheets;
     readonly attribute Element host;