GitLab

Reland of
https://chromium-review.googlesource.com/c/chromium/src/+/2233827

Instead of relying on the v2 unpak folder structure to work around
the paths for generated files being mapped incorrectly, create an
independent v3 unpak folder and add an argument to unpack_pak.py that
allows generated paths to be rebased without assuming the root path
is the location of the pak file.

Bug: 1045266
Change-Id: I0b6c72ff91682b2ca8e74d6e6c7eba5aa950241c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2242654Reviewed-by: dpapad <dpapad@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#779007}