[binding] Migrate XSLTProcessor.idl away from using custom V8 binding.

Source/core/xml/XSLTProcessor.cpp

 /*
  * This file is part of the XSL implementation.
  *
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple, Inc. All rights reserved.
  * Copyright (C) 2005, 2006 Alexey Proskuryakov <ap@webkit.org>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 121 matching lines @@
 
     if (!transformToString(sourceNode, resultMIMEType, resultString, resultEncoding))
         return nullptr;
     return createFragmentForTransformToFragment(resultString, resultMIMEType, *outputDoc);
 }
 
 void XSLTProcessor::setParameter(const String& /*namespaceURI*/, const String& localName, const String& value)
 {
     // FIXME: namespace support?
     // should make a QualifiedName here but we'd have to expose the impl
+    if (localName.isNull() || value.isNull())
+        return;
     m_parameters.set(localName, value);
 }
 
 String XSLTProcessor::getParameter(const String& /*namespaceURI*/, const String& localName) const
 {
     // FIXME: namespace support?
     // should make a QualifiedName here but we'd have to expose the impl
+    if (localName.isNull())
+        return String();
     return m_parameters.get(localName);
 }
 
 void XSLTProcessor::removeParameter(const String& /*namespaceURI*/, const String& localName)
 {
     // FIXME: namespace support?
+    if (localName.isNull())
+        return;
     m_parameters.remove(localName);
 }
 
 void XSLTProcessor::reset()
 {
     m_stylesheet.clear();
     m_stylesheetRootNode.clear();
     m_parameters.clear();
 }
 
 void XSLTProcessor::trace(Visitor* visitor)
 {
     visitor->trace(m_stylesheet);
     visitor->trace(m_stylesheetRootNode);
     visitor->trace(m_document);
 }
 
 } // namespace blink