Paint solid color background into both scrolling contents layer and graphics layer.

Paint solid color background into both scrolling contents layer and graphics layer.

BUG=660472
TEST=paint/invalidation/composited-overflow-with-borderbox-background, PaintLayerScrollableAreaTest.CanPaintBackgroundOntoScrollingContentsLayer
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Committed: https://crrev.com/f6df28f2345268e2e3503e769a5eedf69a1f118a
Cr-Commit-Position: refs/heads/master@{#435280}

[flackr, 2016-11-17 19:40:02]

Description was changed from

==========
Paint solid color background into both scrolling contents layer and graphics
layer.

BUG=660472
TEST=paint/invalidation/composited-overflow-with-borderbox-background,
PaintLayerScrollableAreaTest.CanPaintBackgroundOntoScrollingContentsLayer
==========

to

==========
Paint solid color background into both scrolling contents layer and graphics
layer.

BUG=660472
TEST=paint/invalidation/composited-overflow-with-borderbox-background,
PaintLayerScrollableAreaTest.CanPaintBackgroundOntoScrollingContentsLayer
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

[flackr, 2016-11-17 19:41:58]

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

[flackr, 2016-11-17 19:41:59]

Hey,

This patch will let us paint solid color backgrounds into both the scrolling
contents layer and graphics layer. This lets us correctly composite solid color
border-box backgrounds while preserving sub-pixel anti-aliasing in the scrolling
content (e.g. pages like gmail with custom scrollbars as long as the scroller is
also a stacking context).

PTAL, thanks!

[chrishtr, 2016-11-17 20:55:40]

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp (right):

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp:185: if (layer ==
(&style()->backgroundLayers()) &&
What if there are later layers in the iteration that paint on top of this
background color?

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
File
third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
(right):

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp:180:
m_backgroundPaintsOntoGraphicsLayer(true) {
false

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/paint/PaintLayer.h (right):

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/paint/PaintLayer.h:506: // Returns which layers
backgrounds should be painted into for overflow
s/layers/GraphicsLayers

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/paint/PaintLayerScrollableAreaTest.cpp
(right):

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/paint/PaintLayerScrollableAreaTest.cpp:22:
BackgroundPaintLocation backgroundPaintLocation(const char* elementId) {
Is one of the tests below exercising solid-color backgrounds?

[flackr, 2016-11-17 23:38:01]

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp (right):

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp:185: if (layer ==
(&style()->backgroundLayers()) &&
On 2016/11/17 at 20:55:39, chrishtr wrote:
> What if there are later layers in the iteration that paint on top of this
> background color?

The background color is always the last layer, there is a check that this is
indeed the last layer on line 163. So this case of painting to both layers only
happens when this is the only layer in the layer list.

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
File
third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
(right):

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp:180:
m_backgroundPaintsOntoGraphicsLayer(true) {
On 2016/11/17 at 20:55:39, chrishtr wrote:
> false

Done.

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/paint/PaintLayer.h (right):

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/paint/PaintLayer.h:506: // Returns which layers
backgrounds should be painted into for overflow
On 2016/11/17 at 20:55:39, chrishtr wrote:
> s/layers/GraphicsLayers

Done.

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
File third_party/WebKit/Source/core/paint/PaintLayerScrollableAreaTest.cpp
(right):

https://codereview.chromium.org/2511893002/diff/1/third_party/WebKit/Source/c...
third_party/WebKit/Source/core/paint/PaintLayerScrollableAreaTest.cpp:22:
BackgroundPaintLocation backgroundPaintLocation(const char* elementId) {
On 2016/11/17 at 20:55:39, chrishtr wrote:
> Is one of the tests below exercising solid-color backgrounds?

Yes, scroller10 and scroller13 test solid color backgrounds which paint into
both layers. But I just realized I should add a test for a partially transparent
background which definitely cannot be painted into both layers, which I've added
as scroller17.

[chrishtr, 2016-11-18 00:16:23]

lgtm

[flackr, 2016-11-28 20:48:06]

The CQ bit was checked by flackr@chromium.org

[flackr, 2016-11-28 20:48:07]

The patchset sent to the CQ was uploaded after l-g-t-m from
chrishtr@chromium.org
Link to the patchset: https://codereview.chromium.org/2511893002/#ps40001
(title: "Merge with master")

[commit-bot: I haz the power, 2016-11-28 20:49:33]

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, 2016-11-28 21:40:18]

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

[commit-bot: I haz the power, 2016-11-28 21:40:19]

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_...)
  win_chromium_x64_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[flackr, 2016-11-29 18:12:19]

The CQ bit was checked by flackr@chromium.org

[flackr, 2016-11-29 18:12:19]

The patchset sent to the CQ was uploaded after l-g-t-m from
chrishtr@chromium.org
Link to the patchset: https://codereview.chromium.org/2511893002/#ps60001
(title: "Rebaseline new test.")

[commit-bot: I haz the power, 2016-11-29 18:12:46]

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, 2016-11-29 20:34:57]

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

[commit-bot: I haz the power, 2016-11-29 20:34:58]

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_...)

[flackr, 2016-11-30 14:52:24]

The CQ bit was checked by flackr@chromium.org

[flackr, 2016-11-30 14:52:24]

The patchset sent to the CQ was uploaded after l-g-t-m from
chrishtr@chromium.org
Link to the patchset: https://codereview.chromium.org/2511893002/#ps80001
(title: "Add Mac rebaselines.")

[commit-bot: I haz the power, 2016-11-30 14:52:36]

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, 2016-11-30 16:21:14]

CQ is committing da patch.

Bot data: {"patchset_id": 80001, "attempt_start_ts": 1480517544389500,
"parent_rev": "089c53307e0c8fb3d4234f64c7c6b9df960a74d5", "commit_rev":
"bd355711d8b80dd8853180c4ff43cb32f32996f8"}

[commit-bot: I haz the power, 2016-11-30 16:21:37]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2016-11-30 16:26:07]

Description was changed from

==========
Paint solid color background into both scrolling contents layer and graphics
layer.

BUG=660472
TEST=paint/invalidation/composited-overflow-with-borderbox-background,
PaintLayerScrollableAreaTest.CanPaintBackgroundOntoScrollingContentsLayer
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
==========

to

==========
Paint solid color background into both scrolling contents layer and graphics
layer.

BUG=660472
TEST=paint/invalidation/composited-overflow-with-borderbox-background,
PaintLayerScrollableAreaTest.CanPaintBackgroundOntoScrollingContentsLayer
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Committed: https://crrev.com/f6df28f2345268e2e3503e769a5eedf69a1f118a
Cr-Commit-Position: refs/heads/master@{#435280}
==========

[commit-bot: I haz the power, 2016-11-30 16:26:08]

Patchset 5 (id:??) landed as
https://crrev.com/f6df28f2345268e2e3503e769a5eedf69a1f118a
Cr-Commit-Position: refs/heads/master@{#435280}