[LayoutNG] Fix shape bug, when inserting a new shelf between others.

This fixes an issue, where we didn't copy across any shape exclusion
data when inserting a new shelf between two other shelves.

Bug: 635619
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: Ib26359ab8ac677034ec4e51f2adf1987dadbd91c
Reviewed-on: https://chromium-review.googlesource.com/1255145
Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595535}
2 files changed