Fix placement of overlay scrollbars on high DPI with box shadow.

Fix placement of overlay scrollbars on high DPI with box shadow.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  Some ancestor clipping
scenarios were also broken.  This patch cleans up the logic and adds comments
and test coverage.

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Committed: https://crrev.com/509c59b3500ee9d2fb244c23cdc6abf528a5bee0
Cr-Commit-Position: refs/heads/master@{#421058}

[skobes, 2016-09-23 03:09:20]

Description was changed from

==========
[WIP] fix scrollbar placement

BUG=635722
==========

to

==========
[WIP] fix scrollbar placement

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[skobes, 2016-09-23 03:09:26]

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

[commit-bot: I haz the power, 2016-09-23 03:09:52]

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, 2016-09-23 04:13:15]

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

[commit-bot: I haz the power, 2016-09-23 04:13:16]

Dry run: Try jobs failed on following builders:
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[skobes, 2016-09-23 23:03:54]

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

[commit-bot: I haz the power, 2016-09-23 23:04:22]

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

[skobes, 2016-09-23 23:33:32]

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

[skobes, 2016-09-23 23:33:44]

Description was changed from

==========
[WIP] fix scrollbar placement

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

to

==========
Fix placement of overlay scrollbars on high DPI.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  This patch cleans up the logic
and adds comments and test coverage.

BUG=635722
==========

[commit-bot: I haz the power, 2016-09-23 23:34:12]

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

[skobes, 2016-09-23 23:34:18]

Description was changed from

==========
Fix placement of overlay scrollbars on high DPI.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  This patch cleans up the logic
and adds comments and test coverage.

BUG=635722
==========

to

==========
Fix placement of overlay scrollbars on high DPI displays.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  This patch cleans up the logic
and adds comments and test coverage.

BUG=635722
==========

[skobes, 2016-09-23 23:34:30]

Patchset #1 (id:1) has been deleted

[skobes, 2016-09-23 23:34:36]

Patchset #1 (id:20001) has been deleted

[skobes, 2016-09-23 23:34:44]

Patchset #1 (id:40001) has been deleted

[skobes, 2016-09-23 23:40:10]

Patchset #1 (id:60001) has been deleted

[skobes, 2016-09-23 23:41:04]

Description was changed from

==========
Fix placement of overlay scrollbars on high DPI displays.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  This patch cleans up the logic
and adds comments and test coverage.

BUG=635722
==========

to

==========
Fix placement of overlay scrollbars on high DPI displays.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  This patch cleans up the logic
and adds comments and test coverage.

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[skobes, 2016-09-23 23:41:12]

Patchset #1 (id:80001) has been deleted

[skobes, 2016-09-23 23:45:05]

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

[commit-bot: I haz the power, 2016-09-23 23:45:32]

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

[skobes, 2016-09-23 23:46:49]

Description was changed from

==========
Fix placement of overlay scrollbars on high DPI displays.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  This patch cleans up the logic
and adds comments and test coverage.

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

to

==========
Fix placement of overlay scrollbars on high DPI with box shadow.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  This patch cleans up the logic
and adds comments and test coverage.

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[skobes, 2016-09-23 23:48:04]

Description was changed from

==========
Fix placement of overlay scrollbars on high DPI with box shadow.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  This patch cleans up the logic
and adds comments and test coverage.

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

to

==========
Fix placement of overlay scrollbars on high DPI with box shadow.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  Some ancestor clipping
scenarios were also broken.  This patch cleans up the logic and adds comments
and test coverage.

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[commit-bot: I haz the power, 2016-09-24 01:24:00]

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

[commit-bot: I haz the power, 2016-09-24 01:24:01]

Dry run: Try jobs failed on following builders:
  mac_chromium_rel_ng on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/mac_chromium_rel_...)

[skobes, 2016-09-24 01:44:24]

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

[commit-bot: I haz the power, 2016-09-24 01:44:37]

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, 2016-09-24 02:54:30]

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

[commit-bot: I haz the power, 2016-09-24 02:54:34]

Dry run: Try jobs failed on following builders:
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[skobes, 2016-09-24 05:33:15]

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

[commit-bot: I haz the power, 2016-09-24 05:33:24]

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, 2016-09-24 06:48:09]

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

[commit-bot: I haz the power, 2016-09-24 06:48:10]

Dry run: Try jobs failed on following builders:
  linux_chromium_rel_ng on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[skobes, 2016-09-24 14:41:49]

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

[commit-bot: I haz the power, 2016-09-24 14:41:57]

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, 2016-09-24 15:37:43]

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

[commit-bot: I haz the power, 2016-09-24 15:37:44]

Dry run: Try jobs failed on following builders:
  win_chromium_x64_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[skobes, 2016-09-24 16:23:24]

Patchset #1 (id:100001) has been deleted

[skobes, 2016-09-24 16:23:35]

Patchset #1 (id:120001) has been deleted

[skobes, 2016-09-24 16:23:45]

Patchset #1 (id:140001) has been deleted

[skobes, 2016-09-24 20:05:59]

skobes@chromium.org changed reviewers:
+ chrishtr@chromium.org, vollick@chromium.org

[skobes, 2016-09-24 20:08:35]

FYI I removed the adjustment by PaintLayer::subpixelAccumulation because I
couldn't figure out what it was for, and the tests pass.

It looks like layerTreeAsText doesn't print anything useful with spv2 so I
marked the test failing... let me know if I should do something different there.

[chrishtr, 2016-09-26 23:31:05]

The CQ bit was checked by chrishtr@chromium.org

[chrishtr, 2016-09-26 23:31:05]

lgtm

[commit-bot: I haz the power, 2016-09-26 23:31:39]

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, 2016-09-27 00:56:53]

Description was changed from

==========
Fix placement of overlay scrollbars on high DPI with box shadow.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  Some ancestor clipping
scenarios were also broken.  This patch cleans up the logic and adds comments
and test coverage.

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

to

==========
Fix placement of overlay scrollbars on high DPI with box shadow.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  Some ancestor clipping
scenarios were also broken.  This patch cleans up the logic and adds comments
and test coverage.

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[commit-bot: I haz the power, 2016-09-27 00:56:55]

Committed patchset #1 (id:160001)

[commit-bot: I haz the power, 2016-09-27 01:02:15]

Description was changed from

==========
Fix placement of overlay scrollbars on high DPI with box shadow.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  Some ancestor clipping
scenarios were also broken.  This patch cleans up the logic and adds comments
and test coverage.

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

to

==========
Fix placement of overlay scrollbars on high DPI with box shadow.

CompositedLayerMapping did not position the scrollbar layers correctly when a
non-stacking-context scroller had a box shadow.  Some ancestor clipping
scenarios were also broken.  This patch cleans up the logic and adds comments
and test coverage.

BUG=635722
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Committed: https://crrev.com/509c59b3500ee9d2fb244c23cdc6abf528a5bee0
Cr-Commit-Position: refs/heads/master@{#421058}
==========

[commit-bot: I haz the power, 2016-09-27 01:02:16]

Patchset 1 (id:??) landed as
https://crrev.com/509c59b3500ee9d2fb244c23cdc6abf528a5bee0
Cr-Commit-Position: refs/heads/master@{#421058}