GitLab

Firefox abandoned usage of the moz_bookmarks_roots table since v. 30 and
removed the table in v. 31 in favor of storing relevant info in the
'guid' column of the moz_bookmarks table.

BUG=638977

Review-Url: https://codereview.chromium.org/2296633002
Cr-Commit-Position: refs/heads/master@{#436262}