It's not used and uses basestring, which is not supported in Python 3.

Bug: 1002209
Change-Id: I9df900076978636c4a5c75e84432a8cc02d46909
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1891654Reviewed-by: Anthony Polito <apolito@google.com>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>