'Called by WebKit to determine if a URL is contained in the history.
Args:
url_string: The URL (as string) to check for.
Return:
True if the url is in the history, False otherwise.'

@functools.lru_cache(maxsize=32768)
def historyContains(self, url_string):

    with debug.log_time('sql', 'historyContains'):
        return (url_string in self._history)
