Add some new ScopedTaskEnvironment tests

Bug: 863341, 891670
Change-Id: If583048e9efcc14ab1456153480d1ab2847eb869
Reviewed-on: https://chromium-review.googlesource.com/c/1347271
Commit-Queue: Alex Clarke <alexclarke@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610354}
1 file changed