testRangeHighlightForZeroSizeSlider() {
    // Make sure range highlight spans whole slider before zeroing width.
    twoThumbSlider.setExtent(100);
    twoThumbSlider.getElement().style.width = 0;

    // The setVisible call is used to force a UI update.
    twoThumbSlider.setVisible(true);
    assertEquals(
        'Range highlight size should be 0 when slider size is 0', 0,
        dom.getElement('rangeHighlight').offsetWidth);
  }
Verifies that no error occurs and that the range highlight is sized
correctly for a zero-size slider (i.e. doesn't attempt to set a
negative size). The test tries to resize the slider from its original
size to 0, then checks that the range highlight's size is correctly set
to 0. The size verification is needed because Webkit/Gecko outright
ignore calls to set negative sizes on an element, leaving it at its
former size. IE throws an error in the same situation.
@suppress {strictMissingProperties} suppression added to enable type
checking