Always call UpdateCompositedScrollOffset, not just for the root layer

Bug: 927560
Change-Id: I1d5522aae4f11dd3f5b8947bb089bac1bf19bdb4
Reviewed-on: https://chromium-review.googlesource.com/c/1452701
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: Mason Freed <masonfreed@chromium.org>
Cr-Commit-Position: refs/heads/master@{#628942}
IntSize PaintLayerScrollableArea::OffsetFromResizeCorner(
    const IntPoint& absolute_point) const {
  IntSize element_size = Layer()->PixelSnappedSize();
  if (GetLayoutBox()->ShouldPlaceBlockDirectionScrollbarOnLogicalLeft())
    element_size.SetWidth(0);
  IntPoint resizer_point = IntPoint(element_size);
  IntPoint local_point = RoundedIntPoint(GetLayoutBox()->AbsoluteToLocal(
      FloatPoint(absolute_point), kUseTransforms));
  return local_point - resizer_point;
}

IntSize PaintLayerScrollableArea::OffsetFromResizeCorner(
    const IntPoint& absolute_point) const {
  IntSize element_size = Layer()->PixelSnappedSize();
  if (GetLayoutBox()->ShouldPlaceBlockDirectionScrollbarOnLogicalLeft())
    element_size.SetWidth(0);
  IntPoint resizer_point = IntPoint(element_size);
  IntPoint local_point = RoundedIntPoint(GetLayoutBox()->AbsoluteToLocal(
      FloatPoint(absolute_point), kUseTransforms));
  return local_point - resizer_point;
}
