Allow loading MHTML archive from content scheme

third_party/WebKit/Source/platform/mhtml/MHTMLArchive.h

 /*
  * Copyright (C) 2011 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 80 matching lines @@
     ArchiveResource* mainResource() { return m_mainResource.get(); }
     ArchiveResource* subresourceForURL(const KURL&) const;
 
     DECLARE_TRACE();
 
 private:
     MHTMLArchive();
 
     void setMainResource(ArchiveResource*);
     void addSubresource(ArchiveResource*);
+    static bool canLoadArchive(const KURL&);
 
     Member<ArchiveResource> m_mainResource;
     SubArchiveResources m_subresources;
 };
 
 } // namespace blink
 
 #endif