Test cases for querySelector fast paths.

Test cases for querySelector fast paths.

Historically we only had perf tests for the various fast paths
but that makes it hard to know what's really happening and if a
change in the SelectorQuery code changed behavior (ex.
Searching too many elements but still finding the right answer).

This patch introduces a system that tracks counters inside 
SelectorQuery (only enabled with dchecks) that let us
write tests to verify the fast paths.

I then wrote a bunch of tests and added comments about edge
cases that are handled poorly by the fast paths today.

BUG=703900
Review-Url: https://codereview.chromium.org/2797083002
Cr-Commit-Position: refs/heads/master@{#462526}
Committed: https://chromium.googlesource.com/chromium/src/+/c00d9dec2a75f7ab0ca2220066c93f7749b797f2

[esprehn, 2017-04-06 05:21:24]

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

[commit-bot: I haz the power, 2017-04-06 05:21:43]

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

[esprehn, 2017-04-06 06:18:53]

Description was changed from

==========
Test cases.

BUG=
==========

to

==========
Test cases for querySelector fast paths.

BUG=703900
==========

[commit-bot: I haz the power, 2017-04-06 07:10:55]

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

[commit-bot: I haz the power, 2017-04-06 07:10:56]

Dry run: This issue passed the CQ dry run.

[esprehn, 2017-04-06 08:38:12]

Description was changed from

==========
Test cases for querySelector fast paths.

BUG=703900
==========

to

==========
Test cases for querySelector fast paths.

Historically we only had perf tests for the various fast paths but that makes it
hard to know what's really happening and if a change in the SelectorQuery code
changed behavior (ex. Searching too many elements but still finding the right
answer).

This patch introduces a system that tracks counters inside SelectorQuery (only
enabled with dchecks) that let us write tests to verify the fast paths.

I then wrote a bunch of tests and added comments about edge cases that are
handled poorly by the fast paths today.

BUG=703900
==========

[esprehn, 2017-04-06 08:38:54]

Description was changed from

==========
Test cases for querySelector fast paths.

Historically we only had perf tests for the various fast paths but that makes it
hard to know what's really happening and if a change in the SelectorQuery code
changed behavior (ex. Searching too many elements but still finding the right
answer).

This patch introduces a system that tracks counters inside SelectorQuery (only
enabled with dchecks) that let us write tests to verify the fast paths.

I then wrote a bunch of tests and added comments about edge cases that are
handled poorly by the fast paths today.

BUG=703900
==========

to

==========
Test cases for querySelector fast paths.

Historically we only had perf tests for the various fast paths
but that makes it hard to know what's really happening and if a
change in the SelectorQuery code changed behavior (ex.
Searching too many elements but still finding the right answer).

This patch introduces a system that tracks counters inside 
SelectorQuery (only enabled with dchecks) that let us
write tests to verify the fast paths.

I then wrote a bunch of tests and added comments about edge
cases that are handled poorly by the fast paths today.

BUG=703900
==========

[esprehn, 2017-04-06 08:40:10]

esprehn@chromium.org changed reviewers:
+ dglazkov@chromium.org, meade@chromium.org, rune@opera.com

[rune, 2017-04-06 11:02:33]

lgtm

[esprehn, 2017-04-06 16:46:18]

The CQ bit was checked by esprehn@chromium.org

[commit-bot: I haz the power, 2017-04-06 16:46:56]

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, 2017-04-06 17:22:56]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1491497178843390,
"parent_rev": "d9f2dc22030cf8d465a6c6e31d94b53b581463c1", "commit_rev":
"c00d9dec2a75f7ab0ca2220066c93f7749b797f2"}

[commit-bot: I haz the power, 2017-04-06 17:23:52]

Description was changed from

==========
Test cases for querySelector fast paths.

Historically we only had perf tests for the various fast paths
but that makes it hard to know what's really happening and if a
change in the SelectorQuery code changed behavior (ex.
Searching too many elements but still finding the right answer).

This patch introduces a system that tracks counters inside 
SelectorQuery (only enabled with dchecks) that let us
write tests to verify the fast paths.

I then wrote a bunch of tests and added comments about edge
cases that are handled poorly by the fast paths today.

BUG=703900
==========

to

==========
Test cases for querySelector fast paths.

Historically we only had perf tests for the various fast paths
but that makes it hard to know what's really happening and if a
change in the SelectorQuery code changed behavior (ex.
Searching too many elements but still finding the right answer).

This patch introduces a system that tracks counters inside 
SelectorQuery (only enabled with dchecks) that let us
write tests to verify the fast paths.

I then wrote a bunch of tests and added comments about edge
cases that are handled poorly by the fast paths today.

BUG=703900

Review-Url: https://codereview.chromium.org/2797083002
Cr-Commit-Position: refs/heads/master@{#462526}
Committed:
https://chromium.googlesource.com/chromium/src/+/c00d9dec2a75f7ab0ca2220066c9...
==========

[commit-bot: I haz the power, 2017-04-06 17:23:53]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/chromium/src/+/c00d9dec2a75f7ab0ca2220066c9...