Add some tracing to most expensive accessibility functions.

Add some tracing to most expensive accessibility functions.

To try it out, enable accessibility first, then visit chrome://tracing,
click Record, then check "accessibility". Then do some browsing, go back
and stop tracing, then draw a box around some events to see where time
is being spent.

This will also enable us to add some telemetry benchmarks for accessibility.

BUG=712417
Review-Url: https://codereview.chromium.org/2827443003
Cr-Commit-Position: refs/heads/master@{#465249}
Committed: https://chromium.googlesource.com/chromium/src/+/04d121c277e84e94e8b56de9a6b09bfb76c17d68

[dmazzoni, 2017-04-17 23:50:02]

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

[dmazzoni, 2017-04-17 23:50:08]

The CQ bit was checked by dmazzoni@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-04-17 23:50:42]

Dry run: 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, 2017-04-18 01:23:49]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-04-18 01:23:50]

Dry run: This issue passed the CQ dry run.

[aboxhall, 2017-04-18 05:20:29]

lgtm

Great, looking forward to seeing what this shows up!

[dmazzoni, 2017-04-18 15:44:44]

The CQ bit was checked by dmazzoni@chromium.org

[commit-bot: I haz the power, 2017-04-18 15:45:06]

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, 2017-04-18 15:49:34]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1492530284303500, "parent_rev":
"79d50ca3b3326c45c7d041bc9cd8f5abd64b24cb", "commit_rev":
"04d121c277e84e94e8b56de9a6b09bfb76c17d68"}

[commit-bot: I haz the power, 2017-04-18 15:49:43]

Description was changed from

==========
Add some tracing to most expensive accessibility functions.

To try it out, enable accessibility first, then visit chrome://tracing,
click Record, then check "accessibility". Then do some browsing, go back
and stop tracing, then draw a box around some events to see where time
is being spent.

This will also enable us to add some telemetry benchmarks for accessibility.

BUG=712417
==========

to

==========
Add some tracing to most expensive accessibility functions.

To try it out, enable accessibility first, then visit chrome://tracing,
click Record, then check "accessibility". Then do some browsing, go back
and stop tracing, then draw a box around some events to see where time
is being spent.

This will also enable us to add some telemetry benchmarks for accessibility.

BUG=712417

Review-Url: https://codereview.chromium.org/2827443003
Cr-Commit-Position: refs/heads/master@{#465249}
Committed:
https://chromium.googlesource.com/chromium/src/+/04d121c277e84e94e8b56de9a6b0...
==========

[commit-bot: I haz the power, 2017-04-18 15:49:44]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/04d121c277e84e94e8b56de9a6b0...