message: Use Analyzer's parseUrl utility method to get proper handling of '//' prefixed urls.
diff: import * as path from 'path';
  import * as url from 'url';
  +import {parseUrl} from 'polymer-analyzer/lib/utils';
  import constants from './constants';
  const pathPosix = path.posix;
  @@ -69,8 +70,8 @@ export function isTemplatedUrl(href: UrlString): boolean {
  * `/a/` is correctly treated as a folder path where `/a` is not.
  */
  export function relativeUrl(fromUri: UrlString, toUri: UrlString): UrlString {
  - const fromUrl = url.parse(fromUri)!;
  - const toUrl = url.parse(toUri)!;
  + const fromUrl = parseUrl(fromUri)!;
  + const toUrl = parseUrl(toUri)!;
  // Return the toUri as-is if there are conflicting components which
  // prohibit calculating a relative form.
  if (sharedRelativeUrlProperties.some(
  