Hide Skip Ad tooltip if not visible in Picture-in-Picture window

Bug: 926121, 926679
Change-Id: Ia562854262a4245197577274b3f3fed67bf65853
Reviewed-on: https://chromium-review.googlesource.com/c/1443011
Commit-Queue: François Beaufort <beaufort.francois@gmail.com>
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#627577}(cherry picked from commit 7ffc24cbc9a6a4b5e4afbe023f678f17c51b5449)
Reviewed-on: https://chromium-review.googlesource.com/c/1448240
Reviewed-by: François Beaufort <beaufort.francois@gmail.com>
Cr-Commit-Position: refs/branch-heads/3683@{#106}
Cr-Branched-From: e51029943e0a38dd794b73caaf6373d5496ae783-refs/heads/master@{#625896}
3 files changed