nsIEffectiveTLDService in Firefox 3.5

 Returns the base domain of a URI; that is, the public suffix with a given
 number of additional domain name parts. For example, the result of this method
 for "www.bbc.co.uk", depending on the value of aAdditionalParts parameter, will
 be:

    0 (default) -> bbc.co.uk
    1           -> www.bbc.co.uk

 Similarly, the public suffix for "www.developer.mozilla.org" is "org", and the base
 domain will be:

    0 (default) -> mozilla.org
    1           -> developer.mozilla.org
    2           -> www.developer.mozilla.org

 The base domain will be returned encoded in ASCII/ACE and will be normalized
 according to RFC 3454, i.e. the same encoding returned by nsIURI::GetAsciiHost().
 If consumers wish to compare the result of this method against the host from
 another nsIURI, the host should be obtained using nsIURI::GetAsciiHost().
 In the case of nested URIs, the innermost URI will be used.

 @param   aURI               The URI to be analyzed
 @param   aAdditionalParts   Number of domain name parts to be
                             returned in addition to the public suffix

 @returns the base domain (public suffix plus the requested number of additional parts)

 @throws NS_ERROR_UNEXPECTED 
         or other error returned by nsIIDNService::normalize when 
         the hostname contains characters disallowed in URIs
 @throws NS_ERROR_INSUFFICIENT_DOMAIN_LEVELS
         when there are insufficient subdomain levels in the hostname to satisfy the
         requested aAdditionalParts value.
 @throws NS_ERROR_HOST_IS_IP_ADDRESS
         if aHost is a numeric IPv4 or IPv6 address (as determined by
         the success of a call to PR_StringToNetAddr()).

 @see    getPublicSuffix()

 NOTE: It is strongly recommended to use getBaseDomain() above if a suitable
 nsIURI is available. Only use this method if this is not the case.

 Returns the base domain of a host string. Otherwise identical to getBaseDomain().

 @param   aHost   The host to be analyzed. Any additional parts (e.g. scheme,
                  port, or path) will cause this method to throw. ASCII/ACE and
                  UTF8 encodings are acceptable as input; normalization will
                  be performed as specified in getBaseDomain().

 @see     getBaseDomain()

 Returns the public suffix of a URI. A public suffix is the highest-level domain
 under which individual domains may be registered; it may therefore contain one
 or more dots. For example, the public suffix for "www.bbc.co.uk" is "co.uk",
 because the .uk TLD does not allow the registration of domains at the
 second level ("bbc.uk" is forbidden).

 The public suffix will be returned encoded in ASCII/ACE and will be normalized
 according to RFC 3454, i.e. the same encoding returned by nsIURI::GetAsciiHost().
 If consumers wish to compare the result of this method against the host from
 another nsIURI, the host should be obtained using nsIURI::GetAsciiHost().
 In the case of nested URIs, the innermost URI will be used.

 @param   aURI   The URI to be analyzed

 @returns the public suffix

 @throws NS_ERROR_UNEXPECTED 
         or other error returned by nsIIDNService::normalize when 
         the hostname contains characters disallowed in URIs
 @throws NS_ERROR_HOST_IS_IP_ADDRESS
         if the host is a numeric IPv4 or IPv6 address (as determined by
         the success of a call to PR_StringToNetAddr()).

 NOTE: It is strongly recommended to use getPublicSuffix() above if a suitable
 nsIURI is available. Only use this method if this is not the case.

 Returns the public suffix of a host string. Otherwise identical to getPublicSuffix().

 @param   aHost   The host to be analyzed. Any additional parts (e.g. scheme,
                  port, or path) will cause this method to throw. ASCII/ACE and
                  UTF8 encodings are acceptable as input; normalization will
                  be performed as specified in getBaseDomain().

 @see     getPublicSuffix()