The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/33880922f9981c5db4f91c6cdf702f75f59261c6

commit 33880922f9981c5db4f91c6cdf702f75f59261c6
Author: dmazzoni <dmazzoni@chromium.org>
Date: Sat Feb 25 00:15:45 2017

Mac accessibility: Add support for AXDOMIdentifier

The Mac NSAccessibility protocol uses AXDOMIdentifier as a way to expose
an HTML element's ID.

This will be helpful to enable writing cross-browser accessibility tests.

BUG= 695908 
TBR=aboxhall@chromium.org

Review-Url: https://codereview.chromium.org/2712153002
Cr-Commit-Position: refs/heads/master@{#453011}

[modify] https://crrev.com/33880922f9981c5db4f91c6cdf702f75f59261c6/content/browser/accessibility/accessibility_tree_formatter_mac.mm
[modify] https://crrev.com/33880922f9981c5db4f91c6cdf702f75f59261c6/content/browser/accessibility/browser_accessibility_cocoa.mm
[modify] https://crrev.com/33880922f9981c5db4f91c6cdf702f75f59261c6/content/browser/accessibility/dump_accessibility_tree_browsertest.cc
[add] https://crrev.com/33880922f9981c5db4f91c6cdf702f75f59261c6/content/test/data/accessibility/html/id-expected-mac.txt
[add] https://crrev.com/33880922f9981c5db4f91c6cdf702f75f59261c6/content/test/data/accessibility/html/id.html