Merge 67734 - createBlobURL with no argument causes crash....

WebCore/page/DOMWindow.idl

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 742 matching lines @@
         attribute [Conditional=TOUCH_EVENTS] TouchEventConstructor TouchEvent;
 
         attribute DOMFormDataConstructor FormData;
 
         attribute [Conditional=BLOB|FILE_WRITER] FileErrorConstructor FileError;
         attribute [Conditional=BLOB] FileReaderConstructor FileReader;
 
         attribute [Conditional=BLOB] BlobBuilderConstructor BlobBuilder;
 
 #if defined(ENABLE_BLOB) && ENABLE_BLOB
-        DOMString createBlobURL(in Blob blob);
+        [ConvertNullStringTo=Undefined] DOMString createBlobURL(in Blob blob);
         void revokeBlobURL(in DOMString blobURL);
 #endif
 
 #endif // defined(LANGUAGE_JAVASCRIPT)
 
 #if defined(V8_BINDING) && V8_BINDING
         // window.toString() requires special handling in V8
         [V8DoNotCheckSignature, DoNotCheckDomainSecurity, Custom, DontEnum] DOMString toString();
 #endif // defined(V8_BINDING)
     };
 
 }