Remove legacy label cr-ui-accessibility

Any comments at all? Anyone?

I remember discussing this point over with Dominic and he gave me some corner cases that make the decision not so simple. Personally, I would be in favor of exposing this. It has also been asked by one of our customers who is using this technique in their web app and they cannot easily work around it.

 Issue 594791  has been merged into this issue.

Two bugs have been filed and multiple products are affected, so it seems more clear to me that this is a regression, though the spec is unclear.

I figured out the fix for this and it doesn't break any existing tests, making me confident that this should be fixed and ideally merged so that this gets out to users soon.

An example of what broke:

<input aria-labelledby="label">
<div id="label" aria-hidden="true">Hidden label</div>

In other browsers, and previous versions of Chrome, the text field got the accessible label "Hidden label", but in the latest version of Chrome it gets a blank label (because the label is aria-hidden). We should ignore aria-hidden when explicitly following something like aria-labelledby (but not otherwise).

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8dacc7a16ffdee2d4af5a60f6f9079c22fd7399c

commit 8dacc7a16ffdee2d4af5a60f6f9079c22fd7399c
Author: dmazzoni <dmazzoni@chromium.org>
Date: Tue Apr 26 16:06:21 2016

Accessible name calc should allow aria-labelledby to reference aria-hidden

The new accessible name calculation improved compatibility overall but broke
one specific case, where one element uses aria-labelledby (or aria-describedby)
to reference a subtree that's explicitly aria-hidden. The correct thing to
do here is ignore aria-hidden when an element is referenced explicitly.

<input aria-labelledby="label">
<div id="label" aria-hidden="true">Hidden label</div>

BUG= 595494 

Review URL: https://codereview.chromium.org/1917943002

Cr-Commit-Position: refs/heads/master@{#389798}

[add] https://crrev.com/8dacc7a16ffdee2d4af5a60f6f9079c22fd7399c/third_party/WebKit/LayoutTests/accessibility/name-calc-aria-hidden.html
[modify] https://crrev.com/8dacc7a16ffdee2d4af5a60f6f9079c22fd7399c/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp

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 today so we can take it for tomorrow's Beta release.

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

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6569fe5bbb0fca1b01108549ccbe0916e1d231eb

commit 6569fe5bbb0fca1b01108549ccbe0916e1d231eb
Author: Dominic Mazzoni <dmazzoni@chromium.org>
Date: Thu Apr 28 23:05:15 2016

Merge to M51: Accessible name calc should allow aria-labelledby to reference aria-hidden

The new accessible name calculation improved compatibility overall but broke
one specific case, where one element uses aria-labelledby (or aria-describedby)
to reference a subtree that's explicitly aria-hidden. The correct thing to
do here is ignore aria-hidden when an element is referenced explicitly.

<input aria-labelledby="label">
<div id="label" aria-hidden="true">Hidden label</div>

BUG= 595494 

Review URL: https://codereview.chromium.org/1917943002

Cr-Commit-Position: refs/heads/master@{#389798}
(cherry picked from commit 8dacc7a16ffdee2d4af5a60f6f9079c22fd7399c)

Review URL: https://codereview.chromium.org/1930253002 .

Cr-Commit-Position: refs/branch-heads/2704@{#297}
Cr-Branched-From: 6e53600def8f60d8c632fadc70d7c1939ccea347-refs/heads/master@{#386251}

[add] https://crrev.com/6569fe5bbb0fca1b01108549ccbe0916e1d231eb/third_party/WebKit/LayoutTests/accessibility/name-calc-aria-hidden.html
[modify] https://crrev.com/6569fe5bbb0fca1b01108549ccbe0916e1d231eb/third_party/WebKit/Source/modules/accessibility/AXNodeObject.cpp

Verified the issue on Mac 10.11.4(VoiceOver), Win 7 and Ubuntu 14.04(ChromeVox extension) using 51.0.2704.36 and its working fine.Attached the screen cast of Mac here.
dmazzoni@ : While using NVDA on Win 10 the speech viewer does not read as exactly as above on tab press, though its read correctly when mouse hovered over the list items.
Please review and update if anything is missed.

Deleted: 595494_May_4.mp4 790 KB

595494_May_4.mp4 790 KB Download

I believe NVDA is working as intended, any differences are not related to this bug. Thanks.