Add null-correctness checking to [StrictTypeChecking] methods

Source/bindings/scripts/code_generator_v8.pm

 # Copyright (C) 2005, 2006 Nikolas Zimmermann <zimmermann@kde.org>
 # Copyright (C) 2006 Anders Carlsson <andersca@mac.com>
 # Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
 # Copyright (C) 2006 Alexey Proskuryakov <ap@webkit.org>
 # Copyright (C) 2006 Apple Computer, Inc.
 # Copyright (C) 2007, 2008, 2009, 2012 Google Inc.
 # Copyright (C) 2009 Cameron McCormack <cam@mcc.id.au>
 # Copyright (C) Research In Motion Limited 2010. All rights reserved.
 # Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
 # Copyright (C) 2012 Ericsson AB. All rights reserved.
@@ skipping 2760 matching lines @@
             # If the "StrictTypeChecking" extended attribute is present, and the argument's type is an
             # interface type, then if the incoming value does not implement that interface, a TypeError
             # is thrown rather than silently passing NULL to the C++ code.
             # Per the Web IDL and ECMAScript specifications, incoming values can always be converted
             # to both strings and numbers, so do not throw TypeError if the argument is of these
             # types.
             if ($function->extendedAttributes->{"StrictTypeChecking"}) {
                 my $argValue = "info[$paramIndex]";
                 my $argType = $parameter->type;
                 if (IsWrapperType($argType)) {
-                    $parameterCheckString .= "    if (info.Length() > $paramIndex && !isUndefinedOrNull($argValue) && !V8${argType}::hasInstance($argValue, info.GetIsolate(), worldType(info.GetIsolate()))) {\n";
+                    my $undefinedNullCheck = $parameter->isNullable ? "isUndefinedOrNull($argValue)" : "${argValue}->IsUndefined()";
+                    $parameterCheckString .= "    if (info.Length() > $paramIndex && !$undefinedNullCheck && !V8${argType}::hasInstance($argValue, info.GetIsolate(), worldType(info.GetIsolate()))) {\n";
                     if ($hasExceptionState) {
                         $parameterCheckString .= "        exceptionState.throwTypeError(\"parameter $humanFriendlyIndex is not of type \'$argType\'.\");\n";
                         $parameterCheckString .= "        exceptionState.throwIfNeeded();\n";
                     }else {
                         $parameterCheckString .= "        throwTypeError(ExceptionMessages::failedToExecute(\"$functionName\", \"$interfaceName\", \"parameter $humanFriendlyIndex is not of type \'$argType\'.\"), info.GetIsolate());\n";
                     }
                     $parameterCheckString .= "        return;\n";
                     $parameterCheckString .= "    }\n";
                 }
             }
@@ skipping 3664 matching lines @@
         if ($parameter->type eq "SerializedScriptValue") {
             return 1;
         } elsif (IsIntegerType($parameter->type)) {
             return 1;
         }
     }
     return 0;
 }
 
 1;