The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1596dec56f05b622f72a94f651bbc14ecdde390d

commit 1596dec56f05b622f72a94f651bbc14ecdde390d
Author: jif <jif@chromium.org>
Date: Tue Jun 27 19:17:19 2017

[iOS] Add accessibility labels to Keyboard Accessory View buttons.

BUG= 735582 

Review-Url: https://codereview.chromium.org/2956103002
Cr-Commit-Position: refs/heads/master@{#482706}

[modify] https://crrev.com/1596dec56f05b622f72a94f651bbc14ecdde390d/ios/chrome/app/strings/ios_strings.grd
[modify] https://crrev.com/1596dec56f05b622f72a94f651bbc14ecdde390d/ios/chrome/browser/ui/toolbar/new_keyboard_accessory_view.mm

Tested on 61.0.3145.0 canary build in iPhone 7 (10.2.1), iPhone 6 plus(11.0.0) and iPad mini(9.3.5) 

The A11y labels are added to the new keyboard accessory view