Use children changed events to monitor active descendant changes.

Use children changed events to monitor active descendant changes.

While the backing Blink implementation gets further fleshed out, loosen ChromeVox's output of active descendants by reading it on children change events.

The change makes it so that active descendants are read out when:
- the focused node (node with state focused), has an active descendant
- the incoming event is either children changed or active descendant changed

TEST=drive.google.com; tab to one of the popup buttons; up/down arrow reads options.

Committed: https://crrev.com/433f8e203fb1304aae9305fc429f176cda57f573
Cr-Commit-Position: refs/heads/master@{#414242}

[David Tseng, 2016-08-24 21:25:02]

Description was changed from

==========
Use children changed events to monitor active descendant changes.
==========

to

==========
Use children changed events to monitor active descendant changes.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
==========

[David Tseng, 2016-08-24 21:29:49]

Description was changed from

==========
Use children changed events to monitor active descendant changes.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
==========

to

==========
Use children changed events to monitor active descendant changes.


While the backing Blink implementation gets further fleshed out, loosen
ChromeVox's output of active descendants by reading it on children change
events.


The change makes it so that active descendants are read out when:
- the focused node (node with state focused), has an active descendant
- the incoming event is either children changed or active descendant changed

TEST=drive.google.com; tab to one of the popup buttons; up/down arrow reads
options.
==========

[David Tseng, 2016-08-24 21:29:49]

dtseng@chromium.org changed reviewers:
+ nektar@chromium.org

[David Tseng, 2016-08-24 21:30:43]

We need to make this work with ChromeVox before things get resolved in Blink.
Please take a look.

[dmazzoni, 2016-08-24 22:25:05]

dmazzoni@chromium.org changed reviewers:
+ dmazzoni@chromium.org

[dmazzoni, 2016-08-24 22:25:05]

lgtm

[David Tseng, 2016-08-24 22:30:02]

The CQ bit was checked by dtseng@chromium.org

[commit-bot: I haz the power, 2016-08-24 22:33:00]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[nektarios, 2016-08-24 22:42:34]

lgtm

[commit-bot: I haz the power, 2016-08-25 01:11:30]

Description was changed from

==========
Use children changed events to monitor active descendant changes.


While the backing Blink implementation gets further fleshed out, loosen
ChromeVox's output of active descendants by reading it on children change
events.


The change makes it so that active descendants are read out when:
- the focused node (node with state focused), has an active descendant
- the incoming event is either children changed or active descendant changed

TEST=drive.google.com; tab to one of the popup buttons; up/down arrow reads
options.
==========

to

==========
Use children changed events to monitor active descendant changes.


While the backing Blink implementation gets further fleshed out, loosen
ChromeVox's output of active descendants by reading it on children change
events.


The change makes it so that active descendants are read out when:
- the focused node (node with state focused), has an active descendant
- the incoming event is either children changed or active descendant changed

TEST=drive.google.com; tab to one of the popup buttons; up/down arrow reads
options.
==========

[commit-bot: I haz the power, 2016-08-25 01:11:32]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-25 01:15:04]

Description was changed from

==========
Use children changed events to monitor active descendant changes.


While the backing Blink implementation gets further fleshed out, loosen
ChromeVox's output of active descendants by reading it on children change
events.


The change makes it so that active descendants are read out when:
- the focused node (node with state focused), has an active descendant
- the incoming event is either children changed or active descendant changed

TEST=drive.google.com; tab to one of the popup buttons; up/down arrow reads
options.
==========

to

==========
Use children changed events to monitor active descendant changes.

While the backing Blink implementation gets further fleshed out, loosen
ChromeVox's output of active descendants by reading it on children change
events.

The change makes it so that active descendants are read out when:
- the focused node (node with state focused), has an active descendant
- the incoming event is either children changed or active descendant changed

TEST=drive.google.com; tab to one of the popup buttons; up/down arrow reads
options.

Committed: https://crrev.com/433f8e203fb1304aae9305fc429f176cda57f573
Cr-Commit-Position: refs/heads/master@{#414242}
==========

[commit-bot: I haz the power, 2016-08-25 01:15:05]

Patchset 1 (id:??) landed as
https://crrev.com/433f8e203fb1304aae9305fc429f176cda57f573
Cr-Commit-Position: refs/heads/master@{#414242}