The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/5126c5ebd3e5a72b9e136e6ef6eef5685458c449

commit 5126c5ebd3e5a72b9e136e6ef6eef5685458c449
Author: Aaron Leventhal <aleventhal@chromium.org>
Date: Tue Dec 12 19:14:42 2017

Omnibox: provide "n of m" position info with screen reader search suggestions

The Omnibox provides suggestion text that is friendly to screen reader users.
However, it is not possible for users to know where they are in the overall
list. Normally, screen reader lists provide "n of m" positional info at the
end of each item. Because we are using a bit of a hack so that focus
can stay in the edit box, we need to provide this info ourselves. The
downside of this approach is that the text will not show up as the shorter n/m
on Braille displays, but it's really a minor downside compared with the benefit.

Bug:  792954 
Change-Id: I3b69bc92ed42c59521ddf80cf932323388f650ab
Reviewed-on: https://chromium-review.googlesource.com/817675
Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523503}
[modify] https://crrev.com/5126c5ebd3e5a72b9e136e6ef6eef5685458c449/chrome/browser/ui/cocoa/omnibox/omnibox_view_mac.mm
[modify] https://crrev.com/5126c5ebd3e5a72b9e136e6ef6eef5685458c449/chrome/browser/ui/views/omnibox/omnibox_view_views.cc
[modify] https://crrev.com/5126c5ebd3e5a72b9e136e6ef6eef5685458c449/chrome/browser/ui/views/omnibox/omnibox_view_views_browsertest.cc
[modify] https://crrev.com/5126c5ebd3e5a72b9e136e6ef6eef5685458c449/components/omnibox/browser/autocomplete_controller.h
[modify] https://crrev.com/5126c5ebd3e5a72b9e136e6ef6eef5685458c449/components/omnibox/browser/autocomplete_match_type.cc
[modify] https://crrev.com/5126c5ebd3e5a72b9e136e6ef6eef5685458c449/components/omnibox/browser/autocomplete_match_type.h
[modify] https://crrev.com/5126c5ebd3e5a72b9e136e6ef6eef5685458c449/components/omnibox/browser/autocomplete_match_type_unittest.cc
[modify] https://crrev.com/5126c5ebd3e5a72b9e136e6ef6eef5685458c449/components/omnibox_strings.grdp