IDL: make optional arguments (without default) explicit sometimes

Source/modules/indexeddb/IDBKeyRange.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 17 matching lines @@
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/modules/v8/IDBBindingUtilities.h"
 #include "core/dom/ExceptionCode.h"
 #include "modules/indexeddb/IDBDatabase.h"
 
 namespace blink {
 
 IDBKeyRange* IDBKeyRange::fromScriptValue(ExecutionContext* context, const ScriptValue& value, ExceptionState& exceptionState)
 {
-    if (value.isUndefined() || value.isNull())
+    if (value.isEmpty() || value.isUndefined() || value.isNull())
         return 0;
 
     IDBKeyRange* range = scriptValueToIDBKeyRange(toIsolate(context), value);
     if (range)
         return range;
 
     IDBKey* key = scriptValueToIDBKey(toIsolate(context), value);
     if (!key || !key->isValid()) {
         exceptionState.throwDOMException(DataError, IDBDatabase::notValidKeyErrorMessage);
         return 0;
@@ skipping 85 matching lines @@
     }
     if (upper->isEqual(lower) && (lowerOpen || upperOpen)) {
         exceptionState.throwDOMException(DataError, "The lower key and upper key are equal and one of the bounds is open.");
         return 0;
     }
 
     return IDBKeyRange::create(lower, upper, lowerOpen ? LowerBoundOpen : LowerBoundClosed, upperOpen ? UpperBoundOpen : UpperBoundClosed);
 }
 
 } // namespace blink