IDL: make optional arguments (without default) explicit sometimes

Source/modules/indexeddb/IDBIndex.idl

Index: Source/modules/indexeddb/IDBIndex.idl
diff --git a/Source/modules/indexeddb/IDBIndex.idl b/Source/modules/indexeddb/IDBIndex.idl
index c6d68265bd3abe8affa2514982d3129d2bac2e66..717ef556ad27a9e3930b56d83e1487f7bc4c2224 100644
--- a/Source/modules/indexeddb/IDBIndex.idl
+++ b/Source/modules/indexeddb/IDBIndex.idl
@@ -42,10 +42,10 @@ enum IDBCursorDirection {
     readonly attribute boolean unique;
     readonly attribute boolean multiEntry;
 
-    [CallWith=ScriptState, RaisesException] IDBRequest openCursor([Default=Undefined] optional any range, optional IDBCursorDirection direction = "next");
-    [CallWith=ScriptState, RaisesException] IDBRequest openKeyCursor([Default=Undefined] optional any range, optional IDBCursorDirection direction = "next");
+    [CallWith=ScriptState, RaisesException] IDBRequest openCursor(optional any range, optional IDBCursorDirection direction = "next");
+    [CallWith=ScriptState, RaisesException] IDBRequest openKeyCursor(optional any range, optional IDBCursorDirection direction = "next");
 
     [CallWith=ScriptState, RaisesException] IDBRequest get(any key);
     [CallWith=ScriptState, RaisesException] IDBRequest getKey(any key);
-    [CallWith=ScriptState, RaisesException] IDBRequest count([Default=Undefined] optional any key);
+    [CallWith=ScriptState, RaisesException] IDBRequest count(optional any key);
 };