Trimming at the bottom looses an important datapoint: which is the
oldest commit. To fix this problem, use Middle Out Compression™️ to
creates a better DEPS roll CL description.

Change-Id: I290073d25989b6880a4b608cd2b8f26a300cc3a1
Reviewed-on: https://chromium-review.googlesource.com/c/1415430Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>
Auto-Submit: Marc-Antoine Ruel <maruel@chromium.org>