GitLab

Replaces OnBoundsChanged override which resulted in a lot of path
generation (per-tab + frame) while opening new tabs or resizing the
window.

Also removes a ::GetInkDropMask() override which just generated the same
path.

Bug: chromium:1007546
Change-Id: I0131f9a589c1525e2c0eacd61c9fcd9f6ac05948
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1861016
Auto-Submit: Peter Boström <pbos@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#705972}