Add support for [PutForwards] IDL extended attribute

Source/bindings/tests/idls/TestObject.idl

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary formstrArg, 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.
@@ skipping 286 matching lines @@
     // DeprecateAs
     [DeprecateAs=StaticReadonlyAttribute] static readonly attribute long deprecatedStaticReadOnlyAttr;
     [DeprecateAs=StaticAttribute] static attribute long deprecatedStaticAttr;
     [DeprecateAs=ReadonlyAttribute] readonly attribute long deprecatedReadonlyAttr;
     [DeprecateAs=Attribute] attribute long deprecatedAttr;
 
     [DeprecateAs=Method] void deprecatedMethod();
     [DeprecateAs=StaticMethod] static void deprecatedStaticMethod();
 
     [DeprecateAs=Constant] const unsigned short DEPRECATED_CONSTANT = 1;
+
+    // PutForwards
+    [PutForwards=href] readonly attribute TestNode location;
+    [PutForwards=hrefThrows] readonly attribute TestNode locationWithException;
 };
 
 // The following comment should not generate any code
 // TestObject implements TestImplements;