code: public static Bisect fromDelta(String text1, String delta)
              throws IllegalArgumentException {
          return new Bisect(changesFromDelta(text1, delta));
      }
docs: Given the original text1, and an encoded string which describes the
  operations required to transform text1 into text2, compute the full diff.
  @param text1 Source string for the diff.
  @param delta Delta text.
  @return Array of DiffBase objects or null if invalid.
  @throws IllegalArgumentException If invalid input.