Improve live region performance

Improve live region performance

Previously, we explicitly omitted alert nodes from being processed as live regions to address hangs in ChromeVox.

- before this patch, ChromeVox would generate output for the same live region potentially the same number of times we get a tree change under the live region container; this could be thousands of times
- we walked up the ancestry chain using a recursive call
- we walked up the final container node's ancestry chain looking for a previously outputted live region

Fixes:
- walk up ancestry chain looking for the live region container first
- move logic to check if the live region container was previously processed immediately after (without any tree walking since the map could only contain live region containers)

TEST=manual on Gmail's keyboard shortcuts page (?). Delete a message with '#'. Verify appropriate alert output.
BUG=681417
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2640283004
Cr-Commit-Position: refs/heads/master@{#445469}
Committed: https://chromium.googlesource.com/chromium/src/+/82e8eb7b5935197660fe3ef05c8ef05e9e5d8c26

[David Tseng, 2017-01-19 23:28:34]

Description was changed from

==========
Improve live region performance

Previously, we explicitly omitted alert nodes from being processed as live
regions to address hangs in ChromeVox.

- before this patch, ChromeVox would generate output for the same live region
potentially the same number of times we get a tree change under the live region
container; this could be thousands of times
- we walked up the ancestry chain using a recursive call
- we walked up the final container node's ancestry chain looking for a
previously outputted live region

Fixes:
- walk up ancestry chain looking for the live region container first
- move logic to check if the live region container was previously processed
immediately after (without any tree walking since the map could only contain
live region containers)

TEST=manual on Gmail's keyboard shortcuts page (?). Delete a message with '#'.
Verify appropriate alert output.
BUG=
==========

to

==========
Improve live region performance

Previously, we explicitly omitted alert nodes from being processed as live
regions to address hangs in ChromeVox.

- before this patch, ChromeVox would generate output for the same live region
potentially the same number of times we get a tree change under the live region
container; this could be thousands of times
- we walked up the ancestry chain using a recursive call
- we walked up the final container node's ancestry chain looking for a
previously outputted live region

Fixes:
- walk up ancestry chain looking for the live region container first
- move logic to check if the live region container was previously processed
immediately after (without any tree walking since the map could only contain
live region containers)

TEST=manual on Gmail's keyboard shortcuts page (?). Delete a message with '#'.
Verify appropriate alert output.
BUG=
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
==========

[David Tseng, 2017-01-19 23:31:31]

Description was changed from

==========
Improve live region performance

Previously, we explicitly omitted alert nodes from being processed as live
regions to address hangs in ChromeVox.

- before this patch, ChromeVox would generate output for the same live region
potentially the same number of times we get a tree change under the live region
container; this could be thousands of times
- we walked up the ancestry chain using a recursive call
- we walked up the final container node's ancestry chain looking for a
previously outputted live region

Fixes:
- walk up ancestry chain looking for the live region container first
- move logic to check if the live region container was previously processed
immediately after (without any tree walking since the map could only contain
live region containers)

TEST=manual on Gmail's keyboard shortcuts page (?). Delete a message with '#'.
Verify appropriate alert output.
BUG=
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
==========

to

==========
Improve live region performance

Previously, we explicitly omitted alert nodes from being processed as live
regions to address hangs in ChromeVox.

- before this patch, ChromeVox would generate output for the same live region
potentially the same number of times we get a tree change under the live region
container; this could be thousands of times
- we walked up the ancestry chain using a recursive call
- we walked up the final container node's ancestry chain looking for a
previously outputted live region

Fixes:
- walk up ancestry chain looking for the live region container first
- move logic to check if the live region container was previously processed
immediately after (without any tree walking since the map could only contain
live region containers)

TEST=manual on Gmail's keyboard shortcuts page (?). Delete a message with '#'.
Verify appropriate alert output.
BUG=681417
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
==========

[David Tseng, 2017-01-19 23:31:31]

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

[dmazzoni, 2017-01-23 18:43:02]

lgtm

[David Tseng, 2017-01-23 19:14:33]

The CQ bit was checked by dtseng@chromium.org

[commit-bot: I haz the power, 2017-01-23 19:15:21]

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

[commit-bot: I haz the power, 2017-01-23 20:34:26]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1485198873855810, "parent_rev":
"7a4396053ba2dc9c51a79652f2f5807b8f4f7086", "commit_rev":
"82e8eb7b5935197660fe3ef05c8ef05e9e5d8c26"}

[commit-bot: I haz the power, 2017-01-23 20:34:56]

Description was changed from

==========
Improve live region performance

Previously, we explicitly omitted alert nodes from being processed as live
regions to address hangs in ChromeVox.

- before this patch, ChromeVox would generate output for the same live region
potentially the same number of times we get a tree change under the live region
container; this could be thousands of times
- we walked up the ancestry chain using a recursive call
- we walked up the final container node's ancestry chain looking for a
previously outputted live region

Fixes:
- walk up ancestry chain looking for the live region container first
- move logic to check if the live region container was previously processed
immediately after (without any tree walking since the map could only contain
live region containers)

TEST=manual on Gmail's keyboard shortcuts page (?). Delete a message with '#'.
Verify appropriate alert output.
BUG=681417
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation
==========

to

==========
Improve live region performance

Previously, we explicitly omitted alert nodes from being processed as live
regions to address hangs in ChromeVox.

- before this patch, ChromeVox would generate output for the same live region
potentially the same number of times we get a tree change under the live region
container; this could be thousands of times
- we walked up the ancestry chain using a recursive call
- we walked up the final container node's ancestry chain looking for a
previously outputted live region

Fixes:
- walk up ancestry chain looking for the live region container first
- move logic to check if the live region container was previously processed
immediately after (without any tree walking since the map could only contain
live region containers)

TEST=manual on Gmail's keyboard shortcuts page (?). Delete a message with '#'.
Verify appropriate alert output.
BUG=681417
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2640283004
Cr-Commit-Position: refs/heads/master@{#445469}
Committed:
https://chromium.googlesource.com/chromium/src/+/82e8eb7b5935197660fe3ef05c8e...
==========

[commit-bot: I haz the power, 2017-01-23 20:34:57]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/82e8eb7b5935197660fe3ef05c8e...