GitLab

Some filters have drawing effects even if they have no content.

- Output a no-op display item to ensure a chunk for the filter will
  be created;
- Let CC side know the filter (with or without content) with correct
  visual rect.

Bug: 771643
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: Ic841823706d5547c5c67ffa8c63620251733bd49
Reviewed-on: https://chromium-review.googlesource.com/871834
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Tien-Ren Chen <trchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530744}