GitLab

This CL makes the following changes:
1. Modified layout so that the title/artist text will have more spaces
to the left border when artwork is hidden.
2. Hide artist label and center title label vertically if artist
is empty.
3. Modify artwork image so that it will always appear as a square. (If
the artwork is not a perfect square, we will scale it up/down and clip
the center square of the artwork.)
4. Fix drop down arrow layout bug.

Bug: 1144309
Change-Id: If0c7b0af690483644dede6866f54cde4e3beb2ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2522675Reviewed-by: Tommy Steimel <steimel@chromium.org>
Reviewed-by: Tetsui Ohkubo <tetsui@chromium.org>
Commit-Queue: Jazz Xu <jazzhsu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825006}