Merge to XFA: Add unit test for top-level bookmarks.

Original Review URL: https://codereview.chromium.org/1404723002 .
(cherry picked from commit 7d54a9f70f977ce9b72959ef55dc6300713ccafe)

R=thestig@chromium.org
TBR=thestig@chromium.org

Review URL: https://codereview.chromium.org/1404193002 .
3 files changed