static fromConstant(style) {
    const styleString = Const.unwrap(style);
    if (styleString.length === 0) {
      return SafeStyle.EMPTY;
    }
    assert(
        endsWith(styleString, ';'),
        `Last character of style string is not ';': ${styleString}`);
    assert(
        contains(styleString, ':'),
        'Style string must contain at least one \':\', to ' +
            'specify a "name: value" pair: ' + styleString);
    return SafeStyle.createSafeStyleSecurityPrivateDoNotAccessOrElse(
        styleString);
  }
Creates a SafeStyle object from a compile-time constant string.

`style` should be in the format
`name: value; [name: value; ...]` and must not have any < or >
characters in it. This is so that SafeStyle's contract is preserved,
allowing the SafeStyle to correctly be interpreted as a sequence of CSS
declarations and without affecting the syntactic structure of any
surrounding CSS and HTML.

This method performs basic sanity checks on the format of `style`
but does not constrain the format of `name` and `value`, except
for disallowing tag characters.

@param {!Const} style A compile-time-constant string from which
    to create a SafeStyle.
@return {!SafeStyle} A SafeStyle object initialized to
    `style`.