nsIPermissionManager Interface

 Add permission information for a given URI and permission type. This
 operation will cause the type string to be registered if it does not
 currently exist. If a permission already exists for a given type, it
 will be modified.

 @param uri         the uri to add the permission for
 @param type        a case-sensitive ASCII string, identifying the consumer.
                    Consumers should choose this string to be unique, with
                    respect to other consumers.
 @param permission  an integer representing the desired action (e.g. allow
                    or deny). The interpretation of this number is up to the
                    consumer, and may represent different actions for different
                    types. Consumers may use one of the enumerated permission
                    actions defined above, for convenience.
                    NOTE: UNKNOWN_ACTION (0) is reserved to represent the
                    default permission when no entry is found for a host, and
                    should not be used by consumers to indicate otherwise.

void add(in nsIURI uri, in string type, in PRUint32 permission)

 Remove permission information for a given host string and permission type.
 The host string represents the exact entry in the permission list (such as
 obtained from the enumerator), not a URI which that permission might apply
 to.

 @param host   the host to remove the permission for
 @param type   a case-sensitive ASCII string, identifying the consumer. 
               The type must have been previously registered using the
               add() method.

void remove(in AUTF8String host, in string type)

 Clear permission information for all websites.

void removeAll()

 Test whether a website has permission to perform the given action.
 This requires an exact hostname match, subdomains are not a match.
 @param uri     the uri to be tested
 @param type    a case-sensitive ASCII string, identifying the consumer
 @param return  see add(), param permission. returns UNKNOWN_ACTION when
                there is no stored permission for this uri and / or type.

PRUint32 testExactPermission(in nsIURI uri, in string type)

 Test whether a website has permission to perform the given action.
 @param uri     the uri to be tested
 @param type    a case-sensitive ASCII string, identifying the consumer
 @param return  see add(), param permission. returns UNKNOWN_ACTION when
                there is no stored permission for this uri and / or type.

PRUint32 testPermission(in nsIURI uri, in string type)