_scopeKeyframes(rule, scopeId) {
    // Animation names are of the form [\w-], so ensure that the name regex does not partially apply
    // to similarly named keyframe names by checking for a word boundary at the beginning and
    // a non-word boundary or `-` at the end.
    rule.keyframesNameRx = new RegExp(`\\b${rule['keyframesName']}(?!\\B|-)`, 'g');
    rule.transformedKeyframesName = rule['keyframesName'] + '-' + scopeId;
    rule.transformedSelector = rule.transformedSelector || rule['selector'];
    rule['selector'] = rule.transformedSelector.replace(
        rule['keyframesName'], rule.transformedKeyframesName);
  }
Transforms `@keyframes` names to be unique for the current host.
Example: @keyframes foo-anim -> @keyframes foo-anim-x-foo-0

@param {StyleNode} rule
@param {string} scopeId