[iOS][MF] New strings for Manual Fallback

Add strings used in Manual Fallback and in the new Autofill input
accessory bar design.

Bug: 845472
Cq-Include-Trybots: luci.chromium.try:ios-simulator-full-configs;master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I1d4c6c89ee74853d76b0890c19226a1ce9000d59
Reviewed-on: https://chromium-review.googlesource.com/1179826
Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584756}
1 file changed