cbuildbot: Add --repo-cache option.

Give the builders an option to give us a warm repo cache to copy in if
we need to create our build root from scratch. This allows us to avoid
overloading GoB when we bring up large numbers of new builders.


Change-Id: Ib79f219554b4a8e0e256f366916c376d716025d0
Reviewed-on: https://chromium-review.googlesource.com/348011
Commit-Ready: Don Garrett <dgarrett@chromium.org>
Tested-by: Don Garrett <dgarrett@chromium.org>
Reviewed-by: Don Garrett <dgarrett@chromium.org>
(cherry picked from commit 0af6ba52f3943e09ee84eb90954ffbf4ddcd086b)
Reviewed-on: https://chromium-review.googlesource.com/351261
Reviewed-by: Josafat Garcia <josafat@chromium.org>
Commit-Queue: Josafat Garcia <josafat@chromium.org>
Tested-by: Josafat Garcia <josafat@chromium.org>
2 files changed