[iOS][Translate] Adds a feature and chrome://flags entry for compact infobar

Bug: 910994
Change-Id: Icd7f498b2916df7e0f89c5c285e50fe64a1c132c
Reviewed-on: https://chromium-review.googlesource.com/c/1381875
Reviewed-by: anthonyvd <anthonyvd@chromium.org>
Commit-Queue: Moe Ahmadi <mahmadi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#617676}
5 files changed