The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/e7d3cad741a52f6d40bc14b211c9fe372f57481d

commit e7d3cad741a52f6d40bc14b211c9fe372f57481d
Author: dmazzoni <dmazzoni@chromium.org>
Date: Fri Apr 29 21:47:07 2016

Don't send focus accessibility events when tab isn't focused.

This regressed in r383885 (https://codereview.chromium.org/1815933002).
I meant to check if the focus callback was null, but instead I was
checking if the lazy instance pointer to the callback was null, which
is never true.

BUG= 608033 

Review-Url: https://codereview.chromium.org/1932383002
Cr-Commit-Position: refs/heads/master@{#390772}

[modify] https://crrev.com/e7d3cad741a52f6d40bc14b211c9fe372f57481d/content/browser/accessibility/browser_accessibility_manager.cc

Your change meets the bar and is auto-approved for M51 (branch: 2704)

Please merge your change to M51 branch 2704 before 5:00 PM PST, Monday (05/02/16), so we can take it in for next week M51 beta release. Thank you.

All Support for Android 

Merging now

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/daae3dc469b408b754e019bf49513494790cfc33

commit daae3dc469b408b754e019bf49513494790cfc33
Author: Dominic Mazzoni <dmazzoni@chromium.org>
Date: Mon May 02 17:34:27 2016

Merge to M51: Don't send focus accessibility events when tab isn't focused.

This regressed in r383885 (https://codereview.chromium.org/1815933002).
I meant to check if the focus callback was null, but instead I was
checking if the lazy instance pointer to the callback was null, which
is never true.

BUG= 608033 

Review-Url: https://codereview.chromium.org/1932383002
Cr-Commit-Position: refs/heads/master@{#390772}
(cherry picked from commit e7d3cad741a52f6d40bc14b211c9fe372f57481d)

Review URL: https://codereview.chromium.org/1938043002 .

Cr-Commit-Position: refs/branch-heads/2704@{#335}
Cr-Branched-From: 6e53600def8f60d8c632fadc70d7c1939ccea347-refs/heads/master@{#386251}

[modify] https://crrev.com/daae3dc469b408b754e019bf49513494790cfc33/content/browser/accessibility/browser_accessibility_manager.cc

Tested the same on win10 chrome version 51.0.2704.36 - Pressing Ctrl+L focusses the address bar and the screen reader is working fine.