void ScrollableArea::scrollPositionChanged(const IntPoint& position)
{
    IntPoint oldPosition = scrollPosition();
    // Tell the derived class to scroll its contents.
    setScrollOffset(position);

    Scrollbar* verticalScrollbar = this->verticalScrollbar();

    // Tell the scrollbars to update their thumb postions.
    if (Scrollbar* horizontalScrollbar = this->horizontalScrollbar()) {
        horizontalScrollbar->offsetDidChange();
        if (horizontalScrollbar->isOverlayScrollbar() && !hasLayerForHorizontalScrollbar()) {
            if (!verticalScrollbar)
                horizontalScrollbar->invalidate();
            else {
                // If there is both a horizontalScrollbar and a verticalScrollbar,
                // then we must also invalidate the corner between them.
                IntRect boundsAndCorner = horizontalScrollbar->boundsRect();
                boundsAndCorner.setWidth(boundsAndCorner.width() + verticalScrollbar->width());
                horizontalScrollbar->invalidateRect(boundsAndCorner);
            }
        }
    }
    if (verticalScrollbar) {
        verticalScrollbar->offsetDidChange();
        if (verticalScrollbar->isOverlayScrollbar() && !hasLayerForVerticalScrollbar())
            verticalScrollbar->invalidate();
    }

    if (scrollPosition() != oldPosition)
        scrollAnimator()->notifyContentAreaScrolled();
}
void ScrollableArea::scrollPositionChanged(const DoublePoint& position, ScrollType scrollType)
{
    TRACE_EVENT0("blink", "ScrollableArea::scrollPositionChanged");

    DoublePoint oldPosition = scrollPositionDouble();
    DoublePoint truncatedPosition = shouldUseIntegerScrollOffset() ? flooredIntPoint(position) : position;

    // Tell the derived class to scroll its contents.
    setScrollOffset(truncatedPosition, scrollType);

    Scrollbar* verticalScrollbar = this->verticalScrollbar();

    // Tell the scrollbars to update their thumb postions.
    if (Scrollbar* horizontalScrollbar = this->horizontalScrollbar()) {
        horizontalScrollbar->offsetDidChange();
        if (horizontalScrollbar->isOverlayScrollbar() && !hasLayerForHorizontalScrollbar()) {
            if (!verticalScrollbar)
                horizontalScrollbar->invalidate();
            else {
                // If there is both a horizontalScrollbar and a verticalScrollbar,
                // then we must also invalidate the corner between them.
                IntRect boundsAndCorner = horizontalScrollbar->boundsRect();
                boundsAndCorner.setWidth(boundsAndCorner.width() + verticalScrollbar->width());
                horizontalScrollbar->invalidateRect(boundsAndCorner);
            }
        }
    }
    if (verticalScrollbar) {
        verticalScrollbar->offsetDidChange();
        if (verticalScrollbar->isOverlayScrollbar() && !hasLayerForVerticalScrollbar())
            verticalScrollbar->invalidate();
    }

    if (scrollPositionDouble() != oldPosition) {
        // FIXME: Pass in DoubleSize. crbug.com/414283.
        scrollAnimator()->notifyContentAreaScrolled(toFloatSize(scrollPositionDouble() - oldPosition));
    }

    scrollAnimator()->setCurrentPosition(toFloatPoint(position));
}