[blink] Unify PaintLayerClipper behavior with kIgnoreOverflowClip

[blink] Unify PaintLayerClipper behavior with kIgnoreOverflowClip

Prior to this CL, the behavior of GeometryMapper version and non-GM
version of PaintLayerClipper was inconsistent with kIgnoreOverflowClip
when both CSS clip and overflow clip present on the painting root.

       | CSS clip | Overflow clip | Both
-------+----------+---------------+--------
GM     | Applied  | Skipped       | Skipped
Non-GM | Applied  | Skipped       | Applied

Also the GM-version applies only CSS clip when both present and
context.root_layer == layer_. (While non-GM applies both)

This CL changes the behavior so that both CSS clip and overflow clip are
ignored whether both or either one present. It is believed that it will
also fix a bug that prevented us from enabling impl-side scrolling on
scrollers that has CSS clip.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2856373002
Cr-Commit-Position: refs/heads/master@{#469449}
Committed: https://chromium.googlesource.com/chromium/src/+/bd513eeb478c279634ca95af0344d68b0d95853e

[trchen, 2017-05-04 00:31:52]

Description was changed from

==========
[blink] Unify PaintLayerClipper behavior with kIgnoreOverflowClip

Prior to this CL, the behavior of GeometryMapper version and non-GM
version of PaintLayerClipper was inconsistent with kIgnoreOverflowClip
when both CSS clip and overflow clip present on the painting root.

       | CSS clip | Overflow clip | Both
-------+----------+---------------+--------
GM     | Applied  | Skipped       | Skipped
Non-GM | Applied  | Skipped       | Applied

Also the GM-version applies only CSS clip when both present and
context.root_layer == layer_. (While non-GM applies both)

This CL changes the behavior so that both CSS clip and overflow clip are
ignored whether both or either one present. It is believed that it will
also fix a bug that prevented us from enabling impl-side scrolling on
scrollers that has CSS clip.
==========

to

==========
[blink] Unify PaintLayerClipper behavior with kIgnoreOverflowClip

Prior to this CL, the behavior of GeometryMapper version and non-GM
version of PaintLayerClipper was inconsistent with kIgnoreOverflowClip
when both CSS clip and overflow clip present on the painting root.

       | CSS clip | Overflow clip | Both
-------+----------+---------------+--------
GM     | Applied  | Skipped       | Skipped
Non-GM | Applied  | Skipped       | Applied

Also the GM-version applies only CSS clip when both present and
context.root_layer == layer_. (While non-GM applies both)

This CL changes the behavior so that both CSS clip and overflow clip are
ignored whether both or either one present. It is believed that it will
also fix a bug that prevented us from enabling impl-side scrolling on
scrollers that has CSS clip.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[trchen, 2017-05-04 00:33:38]

trchen@chromium.org changed reviewers:
+ chrishtr@chromium.org

[trchen, 2017-05-04 00:33:38]

Split out from  https://codereview.chromium.org/2817053002/
This CL contains only the small subset that changes behavior, without the
complex refactoring.

[trchen, 2017-05-04 00:37:20]

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

[commit-bot: I haz the power, 2017-05-04 00:38:03]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[chrishtr, 2017-05-04 03:29:52]

lgtm

[commit-bot: I haz the power, 2017-05-04 04:24:46]

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

[commit-bot: I haz the power, 2017-05-04 04:24:48]

Dry run: This issue passed the CQ dry run.

[trchen, 2017-05-04 20:24:14]

The CQ bit was checked by trchen@chromium.org

[commit-bot: I haz the power, 2017-05-04 20:24:38]

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, 2017-05-04 20:29:02]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1493929454207670, "parent_rev":
"3618dd3427458c36cd1d912181911799ce6e6504", "commit_rev":
"bd513eeb478c279634ca95af0344d68b0d95853e"}

[commit-bot: I haz the power, 2017-05-04 20:29:19]

Description was changed from

==========
[blink] Unify PaintLayerClipper behavior with kIgnoreOverflowClip

Prior to this CL, the behavior of GeometryMapper version and non-GM
version of PaintLayerClipper was inconsistent with kIgnoreOverflowClip
when both CSS clip and overflow clip present on the painting root.

       | CSS clip | Overflow clip | Both
-------+----------+---------------+--------
GM     | Applied  | Skipped       | Skipped
Non-GM | Applied  | Skipped       | Applied

Also the GM-version applies only CSS clip when both present and
context.root_layer == layer_. (While non-GM applies both)

This CL changes the behavior so that both CSS clip and overflow clip are
ignored whether both or either one present. It is believed that it will
also fix a bug that prevented us from enabling impl-side scrolling on
scrollers that has CSS clip.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

to

==========
[blink] Unify PaintLayerClipper behavior with kIgnoreOverflowClip

Prior to this CL, the behavior of GeometryMapper version and non-GM
version of PaintLayerClipper was inconsistent with kIgnoreOverflowClip
when both CSS clip and overflow clip present on the painting root.

       | CSS clip | Overflow clip | Both
-------+----------+---------------+--------
GM     | Applied  | Skipped       | Skipped
Non-GM | Applied  | Skipped       | Applied

Also the GM-version applies only CSS clip when both present and
context.root_layer == layer_. (While non-GM applies both)

This CL changes the behavior so that both CSS clip and overflow clip are
ignored whether both or either one present. It is believed that it will
also fix a bug that prevented us from enabling impl-side scrolling on
scrollers that has CSS clip.
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2856373002
Cr-Commit-Position: refs/heads/master@{#469449}
Committed:
https://chromium.googlesource.com/chromium/src/+/bd513eeb478c279634ca95af0344...
==========

[commit-bot: I haz the power, 2017-05-04 20:29:20]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/bd513eeb478c279634ca95af0344...