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: Ifac20c066d7c6527574e9a128e4f5d60774824b3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2944646
Auto-Submit: Brian Ryner <bryner@google.com>
Commit-Queue: Dirk Pranke <dpranke@google.com>
Reviewed-by: Dirk Pranke <dpranke@google.com>