nsICertVerificationResult Interface

  This interface reflects a container of
  verification results. Call will not block.

  Obtain an array of human readable strings describing
  the certificate's certified usages.

  Mirrors the results produced by 
  nsIX509Cert::getUsagesArray()

  As of today, this function is a one-shot object,
  only the first call will succeed.
  This allows an optimization in the implementation, 
  ownership of result data will be transfered to caller.

  @param cert The certificate that was verified.
  @param verified The certificate verification result, 
         see constants in nsIX509Cert.
  @param count The number of human readable usages returned.
  @param usages The array of human readable usages.