Adding language detection unittest case.

This test directly calls 'GetLanguage' on the nodes, rather than relying on
the browsertests code.

Test will need to be updated once we actually detect languages.

R=dmazzoni,aboxhall
BUG=889370

Change-Id: I1c280453bb8d03005fd5d0f0b87fe300f156277a
Reviewed-on: https://chromium-review.googlesource.com/c/1377484
Commit-Queue: Chris Hall <chrishall@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#617037}
1 file changed