Mac: Correct CALayer reuse logic

Mac: Correct CALayer reuse logic

This is a bug in how we construct the CALayer tree. The code
originally assumed that we would always re-use the old CALayer
if it existed. This is no longer the case now that we sometimes
use AVSampleBufferDisplayLayers.

With this patch, we ensure that we always put the new CALayer
in the position of the old CALayer.

A unit test for this is coming in another patch, but this one is
being merged back to M52, and the unit test files have changed
dramatically.

BUG=618287
Committed: https://crrev.com/4eff049bf6baef15d02a9c2d019a38e4a50c9731
Cr-Commit-Position: refs/heads/master@{#407561}

[ccameron, 2016-07-25 19:21:18]

Description was changed from

==========
Mac: Correct CALayer reuse logic

BUG=618287
==========

to

==========
Mac: Correct CALayer reuse logic

This is a bug in how we construct the CALayer tree. The code
originally assumed that we would always re-use the old CALayer
if it existed. This is no longer the case now that we sometimes
use AVSampleBufferDisplayLayers.

With this patch, we ensure that we always put the new CALayer
in the position of the old CALayer.

A unit test for this is coming in another patch, but this one is
being merged back to M52, and the unit test files have changed
dramatically.

BUG=618287
==========

[ccameron, 2016-07-25 19:21:18]

ccameron@chromium.org changed reviewers:
+ erikchen@chromium.org

[ccameron, 2016-07-25 19:21:49]

ptal -- this is for merge to M52, so it's a bit urgent.

I'm working on unit tests, but separating that out, cause there are a bazillion
conflicts in that file

[erikchen, 2016-07-25 19:33:41]

lgtm

[ccameron, 2016-07-25 19:38:19]

Thanks!

[ccameron, 2016-07-25 19:38:23]

The CQ bit was checked by ccameron@chromium.org

[commit-bot: I haz the power, 2016-07-25 19:39:09]

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, 2016-07-25 20:22:34]

Description was changed from

==========
Mac: Correct CALayer reuse logic

This is a bug in how we construct the CALayer tree. The code
originally assumed that we would always re-use the old CALayer
if it existed. This is no longer the case now that we sometimes
use AVSampleBufferDisplayLayers.

With this patch, we ensure that we always put the new CALayer
in the position of the old CALayer.

A unit test for this is coming in another patch, but this one is
being merged back to M52, and the unit test files have changed
dramatically.

BUG=618287
==========

to

==========
Mac: Correct CALayer reuse logic

This is a bug in how we construct the CALayer tree. The code
originally assumed that we would always re-use the old CALayer
if it existed. This is no longer the case now that we sometimes
use AVSampleBufferDisplayLayers.

With this patch, we ensure that we always put the new CALayer
in the position of the old CALayer.

A unit test for this is coming in another patch, but this one is
being merged back to M52, and the unit test files have changed
dramatically.

BUG=618287
==========

[commit-bot: I haz the power, 2016-07-25 20:22:35]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-25 20:26:06]

Description was changed from

==========
Mac: Correct CALayer reuse logic

This is a bug in how we construct the CALayer tree. The code
originally assumed that we would always re-use the old CALayer
if it existed. This is no longer the case now that we sometimes
use AVSampleBufferDisplayLayers.

With this patch, we ensure that we always put the new CALayer
in the position of the old CALayer.

A unit test for this is coming in another patch, but this one is
being merged back to M52, and the unit test files have changed
dramatically.

BUG=618287
==========

to

==========
Mac: Correct CALayer reuse logic

This is a bug in how we construct the CALayer tree. The code
originally assumed that we would always re-use the old CALayer
if it existed. This is no longer the case now that we sometimes
use AVSampleBufferDisplayLayers.

With this patch, we ensure that we always put the new CALayer
in the position of the old CALayer.

A unit test for this is coming in another patch, but this one is
being merged back to M52, and the unit test files have changed
dramatically.

BUG=618287

Committed: https://crrev.com/4eff049bf6baef15d02a9c2d019a38e4a50c9731
Cr-Commit-Position: refs/heads/master@{#407561}
==========

[commit-bot: I haz the power, 2016-07-25 20:26:07]

Patchset 1 (id:??) landed as
https://crrev.com/4eff049bf6baef15d02a9c2d019a38e4a50c9731
Cr-Commit-Position: refs/heads/master@{#407561}