Introduces a new git cl command `squash-closed`. Similar to archive,
this will operate on all closed branches. Unlike archive, rather than
removing these branches and potentially leaving their downstreams in a
wedged state, this will squash the branch and appropriately reparent the
downstream. This makes this a good function to run in preparation of a
`git rebase-update`, especially if there are chained git branches, as
this will then shrink any merged branches to a single commit which
should cleanly apply and drop off.
Bug: 40264739
Change-Id: I1836f944d43f5f3dcebbebf06437bef890da96ca
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/6230362
Reviewed-by: Yiwei Zhang <yiwzhang@google.com>
Commit-Queue: Alexander Cooper <alcooper@chromium.org>
Auto-Submit: Alexander Cooper <alcooper@chromium.org>
Reviewed-by: Josip Sokcevic <sokcevic@chromium.org>
Commit-Queue: Yiwei Zhang <yiwzhang@google.com>
