Replace responseType mismatch handling code in XMLHttpRequest::responseJSONSource() with ASSERT

Source/bindings/v8/custom/V8XMLHttpRequestCustom.cpp

 /*
  * Copyright (C) 2008, 2009, 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 79 matching lines @@
     case XMLHttpRequest::ResponseTypeDefault:
     case XMLHttpRequest::ResponseTypeText:
         responseTextAttributeGetterCustom(name, info);
         return;
 
     case XMLHttpRequest::ResponseTypeJSON:
         {
             v8::Isolate* isolate = info.GetIsolate();
 
             ExceptionState es(isolate);
-            ScriptString jsonSource = xmlHttpRequest->responseJSONSource(es);
+            ScriptString jsonSource = xmlHttpRequest->responseJSONSource();
             if (es.throwIfNeeded())
                 return;
 
             if (jsonSource.hasNoValue() || !jsonSource.v8Value()->IsString()) {
                 v8SetReturnValue(info, v8NullWithCheck(isolate));
                 return;
             }
 
             // Catch syntax error.
             v8::TryCatch exceptionCatcher;
@@ skipping 129 matching lines @@
             ASSERT(arrayBufferView);
             xmlHttpRequest->send(arrayBufferView, es);
         } else
             xmlHttpRequest->send(toWebCoreStringWithNullCheck(arg), es);
     }
 
     es.throwIfNeeded();
 }
 
 } // namespace WebCore