ChromeVox should not speak live regions that aren't in the document.

ChromeVox should not speak live regions that aren't in the document.

The underlying issue is that by the time we get around to processing a live
region node from a mutation observer, the node may no longer be part of
the DOM, in which case we should treat it as invisible.

To fix it, fix cvox.DomUtil.hasInvisibleAncestor_ so that it returns
true (invisible) if passed an element that's not actually part of the
document.

BUG=408821
Committed: https://crrev.com/6626c4c105693e908f133c29475666f42f6f42ca
Cr-Commit-Position: refs/heads/master@{#292847}

[dmazzoni, 2014-08-28 23:00:13]

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

[David Tseng, 2014-08-29 16:52:47]

lgtm

[dmazzoni, 2014-09-01 06:42:34]

The CQ bit was checked by dmazzoni@chromium.org

[commit-bot: I haz the power, 2014-09-01 06:43:39]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/dmazzoni@chromium.org/517853002/1

[commit-bot: I haz the power, 2014-09-01 07:38:28]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu/builds/54023)

[commit-bot: I haz the power, 2014-09-01 08:18:14]

Committed patchset #1 (id:1) as 39eaeb6498388cbdb73f4423dea316dec09ae0dd

[commit-bot: I haz the power, 2014-09-10 03:16:00]

Patchset 1 (id:??) landed as
https://crrev.com/6626c4c105693e908f133c29475666f42f6f42ca
Cr-Commit-Position: refs/heads/master@{#292847}