[SPv175+] Create OverflowClip for LayoutSVGForeignObject

This applies the overflow clip on the object and its descendants if the
object clips overflow.

This also fixes crbug.com/771852 for SPv175. The bug fix also changes
behavior of positioned objects under SVG foreignObject (to be correct),
The impact is trivial. See usage data in crbug.com/723076#c8.

Bug: 771643,771852
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I8ecc1c7aaf03c88b1c6a2a1823068e11197695bb
Reviewed-on: https://chromium-review.googlesource.com/862284
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#529919}
37 files changed