Chromium's Blink bug: On DOM ready automatic CSS explode from user-agent defaults to applied styles

Issues: crbug.com/332189, crbug.com/167083

Problem: On DOM ready automatic CSS explode from user-agent defaults to applied styles. The "explode" cased in HTML with at least 3 input elements in form and applied CSS transition by external style sheets to whatever element.

Expected result: no on load transition "explode", fire transition just on call to action, like :hover, DOM className change, etc.

External style input.css
    .foo {
        width: 10em;
        padding: 3em;
        margin: 1em;
        font-size: 200%;
        background-color: red;
        border: 1em solid #eee;
        border-radius: 1em;
        box-shadow: 0 0 1em #aaa;
        transition-duration: 3s; /* transition makes the bug noticable */
    }

Problem cased HTML by at least 3 input elements single input element in form.

Update: On Chrome 52 stable and Chrome 54 canary noticed the bug happens also with single input element.

    <p class=foo>If this box expands in animation, then the issue is still not fixed.</p>
    <form hidden>
        <input>
        <input type=text>
        <input type=email>
    </form>

Test case

If this box expands in animation, then the issue is still not fixed.

As you can see the test case, the transition animation is rendered from user-agent stylesheet defaults, noticeable in "explode" of width, padding, font-size, background-color, border, etc.