Support for json media types as (non-image) mime types.

Source/core/dom/DOMImplementation.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * 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 49 matching lines @@
 
     // From the HTMLDOMImplementation interface
     PassRefPtr<HTMLDocument> createHTMLDocument(const String& title);
 
     // Other methods (not part of DOM)
     static PassRefPtr<Document> createDocument(const String& MIMEType, Frame*, const KURL&, bool inViewSourceMode);
     static PassRefPtr<Document> createDocument(const String& type, const DocumentInit&, bool inViewSourceMode);
 
     static bool isXMLMIMEType(const String& MIMEType);
     static bool isTextMIMEType(const String& MIMEType);
+    static bool isJSONMIMEType(const String& MIMEType);
 
 private:
     explicit DOMImplementation(Document&);
 
     Document& m_document;
 };
 
 } // namespace WebCore
 
 #endif