[Extensions] Test storage APIs for SW without storage permissions.

Change-Id: I02623445a38902900fc80f00a98040712cd6b951
Reviewed-on: https://chromium-review.googlesource.com/c/1468164
Commit-Queue: David Bertoni <dbertoni@chromium.org>
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#631989}
3 files changed