[SPv175+] OverflowControlsClip

Overflow controls (scrollbars, resizers, scroll corners) need to be
clipped by the border box rect. When they would overflow the border
box rect, create a OverflowControlsClip property node and use it when
painting the overflow controls.

Bug: 771643
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_layout_ng;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I96e362c643ec1643d7099273fae11c0943360f10
Reviewed-on: https://chromium-review.googlesource.com/875257
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530698}
11 files changed