IndexedDB: Use [Default] in IDLs to reduce overloads in implementations

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 24cc51c33ef8f1422997ddb1467ac97f7b517ed4..78ef8af286f9bd724f16d4f61901d0fd5a5abbc7 100644
--- a/Source/modules/indexeddb/IDBIndex.idl
+++ b/Source/modules/indexeddb/IDBIndex.idl
@@ -32,16 +32,18 @@
     readonly attribute boolean unique;
     readonly attribute boolean multiEntry;
 
-    [CallWith=ScriptExecutionContext, RaisesException] IDBRequest openCursor(optional IDBKeyRange? range, optional DOMString direction);
-    [CallWith=ScriptExecutionContext, RaisesException] IDBRequest openCursor(any key, optional DOMString direction);
+    [CallWith=ScriptExecutionContext, RaisesException] IDBRequest openCursor([Default=Undefined] optional IDBKeyRange? range, [Default=NullString] optional DOMString direction);
+    [CallWith=ScriptExecutionContext, RaisesException] IDBRequest openCursor(any key, [Default=NullString] optional DOMString direction);
 
-    [CallWith=ScriptExecutionContext, RaisesException] IDBRequest openKeyCursor(optional IDBKeyRange? range, optional DOMString  direction);
-    [CallWith=ScriptExecutionContext, RaisesException] IDBRequest openKeyCursor(any key, optional DOMString direction);
+    [CallWith=ScriptExecutionContext, RaisesException] IDBRequest openKeyCursor([Default=Undefined] optional IDBKeyRange? range, [Default=NullString] optional DOMString  direction);
+    [CallWith=ScriptExecutionContext, RaisesException] IDBRequest openKeyCursor(any key, [Default=NullString] optional DOMString direction);
 
     [CallWith=ScriptExecutionContext, RaisesException] IDBRequest get(IDBKeyRange? key);
     [CallWith=ScriptExecutionContext, RaisesException] IDBRequest get(any key);
+
     [CallWith=ScriptExecutionContext, RaisesException] IDBRequest getKey(IDBKeyRange? key);
     [CallWith=ScriptExecutionContext, RaisesException] IDBRequest getKey(any key);
-    [CallWith=ScriptExecutionContext, RaisesException] IDBRequest count(optional IDBKeyRange? range);
+
+    [CallWith=ScriptExecutionContext, RaisesException] IDBRequest count([Default=Undefined] optional IDBKeyRange? range);
     [CallWith=ScriptExecutionContext, RaisesException] IDBRequest count(any key);
 };