This is a reland of 1c8026d2

Original change's description:
> presubmit_support: Add --all-files options.
> 
> Will be set when --all is passed to git-cl presubmit to execute
> presubmit checks over all files on a repo.
> 
> Bug: 1042324
> Change-Id: I2ebb7c3ec633f9d3a3774314799aa056bc2919c8
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2003071
> Reviewed-by: Anthony Polito <apolito@google.com>
> Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

Bug: 1042324
Change-Id: I452d98972f9b2c6d0a212029bac5aa6af57dce40
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2038055Reviewed-by: Anthony Polito <apolito@google.com>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>