Use flat_set in SurfaceAggregator.

Use flat_set in SurfaceAggregator.

The sets and maps are typically small or empty and created once. flat_set and
flat_map will have better performance for these workloads.

See the bug for histograms of sizes.

Reland of https://codereview.chromium.org/2821353002 with fix.
Reland of https://codereview.chromium.org/2823043002 with fix.

BUG=712295
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
TBR=jbauman@chromium.org

Review-Url: https://codereview.chromium.org/2831663002
Cr-Commit-Position: refs/heads/master@{#465681}
Committed: https://chromium.googlesource.com/chromium/src/+/8dd06bbc3fd157da89a7ed820b306d39ebea64e2

[brettw, 2017-04-19 17:47:13]

Fix

[brettw, 2017-04-19 17:47:44]

One more non-stable iterator I had to change. The original landing is in PS1.

[brettw, 2017-04-19 17:47:48]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2017-04-19 17:48:32]

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, 2017-04-19 18:51:54]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1492624068394520,
"parent_rev": "4d1da988bfeb8c480f8f92af9d328a428050255e", "commit_rev":
"8dd06bbc3fd157da89a7ed820b306d39ebea64e2"}

[commit-bot: I haz the power, 2017-04-19 18:53:06]

Description was changed from

==========
Use flat_set in SurfaceAggregator.

The sets and maps are typically small or empty and created once. flat_set and
flat_map will have better performance for these workloads.

See the bug for histograms of sizes.

Reland of https://codereview.chromium.org/2821353002 with fix.
Reland of https://codereview.chromium.org/2823043002 with fix.

BUG=712295
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
TBR=jbauman@chromium.org
==========

to

==========
Use flat_set in SurfaceAggregator.

The sets and maps are typically small or empty and created once. flat_set and
flat_map will have better performance for these workloads.

See the bug for histograms of sizes.

Reland of https://codereview.chromium.org/2821353002 with fix.
Reland of https://codereview.chromium.org/2823043002 with fix.

BUG=712295
CQ_INCLUDE_TRYBOTS=master.tryserver.blink:linux_trusty_blink_rel
TBR=jbauman@chromium.org

Review-Url: https://codereview.chromium.org/2831663002
Cr-Commit-Position: refs/heads/master@{#465681}
Committed:
https://chromium.googlesource.com/chromium/src/+/8dd06bbc3fd157da89a7ed820b30...
==========

[commit-bot: I haz the power, 2017-04-19 18:53:08]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/8dd06bbc3fd157da89a7ed820b30...