VR: Support loading string resources in unit tests.

To this point, we haven't needed to test code that relies on translated
strings.  The URL bar is about to require such a string, so we need to
include resource capabilities in the test target.

BUG=

Review-Url: https://codereview.chromium.org/2937263002
Cr-Commit-Position: refs/heads/master@{#480115}
2 files changed