GitLab

Implements a test for backward-compatibility between any two versions
of a mojom enum definition.

This will be used to enforce stability checks once a [Stable]
attribute is introduced.

Bug: 1070663
Change-Id: I84c3051337adeb10a8cef0eadd0708548215d0bf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2212890Reviewed-by: Oksana Zhuravlova <oksamyt@chromium.org>
Commit-Queue: Ken Rockot <rockot@google.com>
Cr-Commit-Position: refs/heads/master@{#771985}