testClickAfterMousedown() {
    // Get the center of the thumb at value zero.
    oneThumbSlider.setValue(0);
    /** @suppress {visibility} suppression added to enable type checking */
    const offset = style.getPageOffset(oneThumbSlider.valueThumb);
    /** @suppress {visibility} suppression added to enable type checking */
    const size = style.getSize(oneThumbSlider.valueThumb);
    offset.x += size.width / 2;
    offset.y += size.height / 2;

    const sliderElement = oneThumbSlider.getElement();
    const width = sliderElement.clientWidth - size.width;
    const range = oneThumbSlider.getMaximum() - oneThumbSlider.getMinimum();
    const offsetXAtZero = offset.x;

    // Temporarily control time.
    let theTime = Date.now();
    const saveGoogNow = Date.now;
    Date.now = () => theTime;

    // set coordinate for a particular value.
    const valueOne = 10;
    offset.x = offsetXAtZero + Math.round(valueOne / range * width);
    testingEvents.fireMouseDownEvent(sliderElement, null, offset);
    assertEquals(valueOne, oneThumbSlider.getValue());

    // Verify a click event with another value that follows quickly is
    // ignored.
    /** @suppress {visibility} suppression added to enable type checking */
    theTime += oneThumbSlider.MOUSE_DOWN_DELAY_ / 2;
    const valueTwo = 20;
    offset.x = offsetXAtZero + Math.round(valueTwo / range * width);
    testingEvents.fireClickEvent(sliderElement, null, offset);
    assertEquals(valueOne, oneThumbSlider.getValue());

    // Verify a click later in time does move the thumb.
    /** @suppress {visibility} suppression added to enable type checking */
    theTime += oneThumbSlider.MOUSE_DOWN_DELAY_;
    testingEvents.fireClickEvent(sliderElement, null, offset);
    assertEquals(valueTwo, oneThumbSlider.getValue());

    Date.now = saveGoogNow;
  }
Tests ignoring click event after mousedown event.
     @suppress {checkTypes} suppression added to enable type checking