Pushed by jwein@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/ceaec1476452 Add in a form element and use form.reset to clear form validation. r=Gijs https://hg.mozilla.org/integration/autoland/rev/e778be2565a3 Pull out a reference to classList in handleEvent. r=Gijs https://hg.mozilla.org/integration/autoland/rev/5ff49a14d8d3 Add jsdoc to public methods of custom elements. r=Gijs https://hg.mozilla.org/integration/autoland/rev/c5293d04b409 Move custom attributes to element.dataset. r=Gijs https://hg.mozilla.org/integration/autoland/rev/3172f277e311 Cache references to shadow DOM elements and move the call to reflectFluentStrings to the super-class. r=Gijs https://hg.mozilla.org/integration/autoland/rev/ea256e43a657 Add underscore prefixes to private methods. r=Gijs