chrome_repack_locales: compress .pak files on Chrome OS

For trivial change to resource_bundle.cc:
TBR=sky@chromium.org

Bug: 1017864
Change-Id: I2afbfa8e02f952d03b36112e0093af92753876ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1883292
Commit-Queue: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713205}