ack after first setHTMLUnsafe.');
    assert_equals(JSON.stringify(myElement1.attributeChangedCalls),
      JSON.stringify([]),
      'myElement1.attributeChangedCalls after first setHTMLUnsafe.');

    container.setHTMLUnsafe('<my-element foo=bar>');
    const myElement2 = container.querySelector('my-element');
    assert_equals(myElement1.numConnectedCallback, 1,
      'myElement1.numConnectedCallback after second setHTMLUnsafe.');
    assert_equals(myElement1.numDisconnectedCallback, 1,
      'myElement1