This contains
https://chromium-review.googlesource.com/c/infra/infra/+/2943752 , a
stability fix for Mac (and potential startup performance improvement).

Bug: 1215121
Change-Id: I77a90b8b00ddf0570dc8e0e5821c0b31b60ab79a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2951423Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Brian Ryner <bryner@google.com>