I have verified that all JSON files currently in depot_tools
pass this check.

Change-Id: I8247653a8161adf69b20d0a837b9f7723936ade2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1620308Reviewed-by: Sean McCullough <seanmccullough@chromium.org>
Commit-Queue: Aaron Gable <agable@chromium.org>