code: public static SanitizedContent constantTrustedResourceUri(
        @CompileTimeConstant final String constant) {
      return fromConstant(constant, ContentKind.TRUSTED_RESOURCE_URI, Dir.LTR);
    }
docs: Wraps an assumed-safe trusted_resource_uri constant.
  
  <p>This only accepts compile-time constants, based on the assumption that trusted resource URIs
  that are controlled by the application (and not user input) are considered safe.