Event;

    heightMQL.addListener(event => {
        heightEvent = event;
    });
    widthMQL.addListener(event => {
        widthEvent = event;
    });

    assert_false(heightMQL.matches);
    assert_true(widthMQL.matches);

    iframe.height = "50"; // 200x100 => 200x50
    await waitForChangesReported();

    assert_equals(heightEvent.media, heightMQL.media);
    assert_true(heightEvent.matches);
    assert_true(heightMQL.matches);
    assert_true(widthMQL.matches);

    iframe.width = "100"; // 200x50