[SPInvalidation] Ensure paint invalidation flags are cleared

[SPInvalidation] Ensure paint invalidation flags are cleared

Also fixed a bug about multicol spanner placeholder. We may set paint
invalidation flags on it so we need to clear the flags though we don't
need to invalidate it.

BUG=646176
TEST=existing unit and layout tests
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Committed: https://crrev.com/751e1f52e94d3d611e27571de632b6a8faa7fc34
Cr-Commit-Position: refs/heads/master@{#424608}

[Xianzhu, 2016-10-11 22:00:16]

Description was changed from

==========
[SPInvalidation] Ensure paint invalidation flags are cleared

Also fixed a bug about multicol spanner placeholder. We may set paint
invalidation flags on it so we need to clear the flags though we don't
need to invalidate it.

BUG=646176
TEST=existing unit and layout tests
==========

to

==========
[SPInvalidation] Ensure paint invalidation flags are cleared

Also fixed a bug about multicol spanner placeholder. We may set paint
invalidation flags on it so we need to clear the flags though we don't
need to invalidate it.

BUG=646176
TEST=existing unit and layout tests
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[Xianzhu, 2016-10-11 22:04:31]

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

[chrishtr, 2016-10-11 22:12:42]

https://codereview.chromium.org/2412613003/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/paint/PrePaintTreeWalk.cpp (right):

https://codereview.chromium.org/2412613003/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/paint/PrePaintTreeWalk.cpp:71:
object.getMutableForPainting().clearPaintInvalidationFlags();
The incorrect flags would have been set by parents which are not really the
parents?

Also, could you point me to the corresponding code in SPv1?

[Xianzhu, 2016-10-11 22:37:21]

https://codereview.chromium.org/2412613003/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/paint/PrePaintTreeWalk.cpp (right):

https://codereview.chromium.org/2412613003/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/paint/PrePaintTreeWalk.cpp:71:
object.getMutableForPainting().clearPaintInvalidationFlags();
On 2016/10/11 22:12:42, chrishtr wrote:
> The incorrect flags would have been set by parents which are not really the
> parents?

No, we just missed clearing paint invalidation flags of the placeholder.

> 
> Also, could you point me to the corresponding code in SPv1?

In SPv1, we don't have special handling about placeholders and spanners. We just
walk them in normal layout tree order. For placeholder, the normal
LayoutObject::invalidatePaintIfNeeded() is called which issues no paint
invalidation and clear the paint invalidation flags. For spanner, we force slow
path rect mapping so don't need to care about the paint offset.

For slimmingPaintInvalidation, we need to follow the logical tree order
(placeholder -> spanner) and skip the placeholder to avoid the paint offset from
being calculated twice (because the placeholder and the spanner has the same
geometries, and the placeholder's parent is actually the logical parent of the
spanner). We should not skip clearing paint invalidation flags anyway.

[chrishtr, 2016-10-11 23:02:25]

The CQ bit was checked by chrishtr@chromium.org

[chrishtr, 2016-10-11 23:02:25]

lgtm

[commit-bot: I haz the power, 2016-10-11 23:02:53]

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, 2016-10-12 00:16:24]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-10-12 00:19:55]

Description was changed from

==========
[SPInvalidation] Ensure paint invalidation flags are cleared

Also fixed a bug about multicol spanner placeholder. We may set paint
invalidation flags on it so we need to clear the flags though we don't
need to invalidate it.

BUG=646176
TEST=existing unit and layout tests
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

to

==========
[SPInvalidation] Ensure paint invalidation flags are cleared

Also fixed a bug about multicol spanner placeholder. We may set paint
invalidation flags on it so we need to clear the flags though we don't
need to invalidate it.

BUG=646176
TEST=existing unit and layout tests
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Committed: https://crrev.com/751e1f52e94d3d611e27571de632b6a8faa7fc34
Cr-Commit-Position: refs/heads/master@{#424608}
==========

[commit-bot: I haz the power, 2016-10-12 00:19:55]

Patchset 2 (id:??) landed as
https://crrev.com/751e1f52e94d3d611e27571de632b6a8faa7fc34
Cr-Commit-Position: refs/heads/master@{#424608}