code: static String stripMappingPath(String url, UriMapping mapping) {
          String relativeUrl = url;
          // Uri mapping
          String mappingPath;
          if (mapping == null) {
              mappingPath = null;
          } else {
              mappingPath = mapping.getPath();
          }
  
          // Remove mapping path
          if (mappingPath != null && url.startsWith(mappingPath)) {
              relativeUrl = relativeUrl.substring(mappingPath.length());
          }
          return relativeUrl;
      }
docs: Get the relative url without the mapping url.
  <p/>
  Uses the url and remove the mapping path.
  
  @param url
  incoming relative url
  @return the url, relative to the driver remote url.