Usage of nsIWebContentHandlerInfo Interface

 Gets the auto handler specified for a particular content type
 @param   contentType
          The content type to look up an auto handler for.
 @returns The web service handler that will automatically handle all 
          documents of the specified type. null if there is no automatic
          handler. (Handlers may be registered, just none of them specified
          as "automatic").

nsIWebContentHandlerInfo getAutoHandler(in AString contentType)

 Gets a web handler for the specified service URI
 @param   contentType
          The content type of the service being located
 @param   uri
          The service URI of the handler to locate.
 @returns A web service handler that uses the specified uri.

nsIWebContentHandlerInfo getWebContentHandlerByURI(in AString contentType, in AString uri)

 Specifies the handler to be used to automatically handle all links of a
 certain content type from now on. 
 @param   contentType
          The content type to automatically load with the specified handler
 @param   handler
          A web service handler. If this is null, no automatic action is
          performed and the user must choose.
 @throws  NS_ERROR_NOT_AVAILABLE if the service refered to by |handler| is 
          not already registered.

void setAutoHandler(in AString contentType, in nsIWebContentHandlerInfo handler)

 Gets the list of content handlers for a particular type.
 @param   contentType
          The content type to get handlers for
 @returns An array of nsIWebContentHandlerInfo objects

void getContentHandlers(in AString contentType, out unsigned long count, [array, retval, size_is(count)] out nsIWebContentHandlerInfo handlers)