Add comments about performance of transparent windows and layers

Add comments about performance of transparent windows and layers

Transparent windows and non-opaque layers have significant performance
impact, so add docs.

BUG=none
TBR=sky@chromium.org for documentation change

Review-Url: https://codereview.chromium.org/2698373002
Cr-Commit-Position: refs/heads/master@{#451309}
Committed: https://chromium.googlesource.com/chromium/src/+/b38b621d8f15c6f424160df8a5be8d3398ebd4ad

[James Cook, 2017-02-17 02:03:12]

jamescook@chromium.org changed reviewers:
+ reveman@chromium.org

[James Cook, 2017-02-17 02:03:13]

reveman, PTAL

[reveman, 2017-02-17 02:04:54]

thanks! lgtm

[James Cook, 2017-02-17 02:08:12]

Description was changed from

==========
Add comments about performance of transparent windows and layers

Transparent windows and non-opaque layers have significant performance
impact, so add docs.

BUG=none
==========

to

==========
Add comments about performance of transparent windows and layers

Transparent windows and non-opaque layers have significant performance
impact, so add docs.

BUG=none
TBR=sky@chromium.org for documentation change
==========

[James Cook, 2017-02-17 02:08:25]

The CQ bit was checked by jamescook@chromium.org

[James Cook, 2017-02-17 02:08:45]

jamescook@chromium.org changed reviewers:
+ sky@chromium.org

[James Cook, 2017-02-17 02:08:45]

TBR sky for documentation-only change

[commit-bot: I haz the power, 2017-02-17 02:09:35]

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, 2017-02-17 04:12:40]

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

[commit-bot: I haz the power, 2017-02-17 04:12:42]

Try jobs failed on following builders:
  chromeos_amd64-generic_chromium_compile_only_ng on
master.tryserver.chromium.linux (JOB_TIMED_OUT, no build URL)
  chromium_presubmit on master.tryserver.chromium.linux (JOB_TIMED_OUT, no build
URL)
  linux_chromium_chromeos_rel_ng on master.tryserver.chromium.linux
(JOB_TIMED_OUT, no build URL)

[sky, 2017-02-17 04:17:20]

LGTM - but you have me worried about how frame decorations are implemented in
the mash world. We need the content not fill opaquely so that the frame
decorations rendered in mash show up.

[reveman, 2017-02-17 04:37:37]

On 2017/02/17 at 04:17:20, sky wrote:
> LGTM - but you have me worried about how frame decorations are implemented in
the mash world. We need the content not fill opaquely so that the frame
decorations rendered in mash show up.

Take a look at
https://docs.google.com/a/google.com/document/d/1TKftrarbQ_lOTmhYm81__gKK0K8-...
if interested in why it's a good idea to avoid marking layers as non-opaque.
Having the window frame be marked as non-opaque is not critical but it would be
nice to improve that if possible. Maybe replacing the "fill opaquely" property
with "opaque region" would help as that would allow the compositor to improve
occlusion culling even if the complete layer is not opaque.

[James Cook, 2017-02-17 15:03:53]

The CQ bit was checked by jamescook@chromium.org

[commit-bot: I haz the power, 2017-02-17 15:04:05]

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, 2017-02-17 15:39:29]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1487343833881840, "parent_rev":
"44243c3dbc42d90b31f410ba8a778105dc11da6b", "commit_rev":
"b38b621d8f15c6f424160df8a5be8d3398ebd4ad"}

[commit-bot: I haz the power, 2017-02-17 15:40:00]

Description was changed from

==========
Add comments about performance of transparent windows and layers

Transparent windows and non-opaque layers have significant performance
impact, so add docs.

BUG=none
TBR=sky@chromium.org for documentation change
==========

to

==========
Add comments about performance of transparent windows and layers

Transparent windows and non-opaque layers have significant performance
impact, so add docs.

BUG=none
TBR=sky@chromium.org for documentation change

Review-Url: https://codereview.chromium.org/2698373002
Cr-Commit-Position: refs/heads/master@{#451309}
Committed:
https://chromium.googlesource.com/chromium/src/+/b38b621d8f15c6f424160df8a5be...
==========

[commit-bot: I haz the power, 2017-02-17 15:40:02]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/b38b621d8f15c6f424160df8a5be...