[omnibox] Prevent re-addition of ellipsis to tail suggestions

The autocomplete code could re-apply the tail suggest ellipsis to a
set of suggestions. This change prevents the subsequent additions to
suggestions which already have it.

Bug: 931245
Change-Id: Id8e9309407a2f477ed57080bb6f6b2fd0b554348
Reviewed-on: https://chromium-review.googlesource.com/c/1466153
Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Commit-Queue: Kevin Bailey <krb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#631526}
2 files changed