GitLab

Remove GridLayout manager for the holding_space_item_chips_container
in favor of a simple custom layout. The GridLayout manager seems to be
unwieldy when trying to remove items.

Clean up hard-coded padding values.

Bug: 1129321
Change-Id: I065c4b5c8acc9822f6a6385660a50a0a77ee98a1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2415280
Commit-Queue: Ahmed Mehfooz <amehfooz@chromium.org>
Reviewed-by: David Black <dmblack@google.com>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809072}