Fix LayoutObject::paintingLayer() about multicol spanner

Fix LayoutObject::paintingLayer() about multicol spanner

This fixes LayoutObject::paintLayer() for the following case:
<div style="columns: 3">
  <div style="column-span: all">
    <div style="overflow: hidden"></div>
  </div>
</div>

The inner div has a non-self-painting layer whose parent layer is the
multicol flow thread layer because layout tree and layer tree structure
follows the dom structure. However, the multicol flow thread layer is
not the actual painting layer but the column container layer is.

When looking for the painting layer, we need to follow the layout tree
instead of the layer tree and skip to the multicol container when we see
a spanner.

BUG=611609
TEST=LayoutObjectTest.PaintingLayerOfOverflowClipLayerUnderColumnSpanAll

Committed: https://crrev.com/db39a0e1882876a8c833821caf0544e8155eaa72
Cr-Commit-Position: refs/heads/master@{#396259}

[Xianzhu, 2016-05-25 23:25:35]

wangxianzhu@chromium.org changed reviewers:
+ mstensho@opera.com

[Xianzhu, 2016-05-26 17:43:16]

wangxianzhu@chromium.org changed reviewers:
+ chrishtr@chromium.org
- mstensho@opera.com

[Xianzhu, 2016-05-26 17:43:16]

mstensho@opera.com is on vacation.

[mstensho (USE GERRIT), 2016-05-26 17:57:31]

mstensho@opera.com changed reviewers:
+ mstensho@opera.com

[mstensho (USE GERRIT), 2016-05-26 17:57:32]

lgtm

(I haven't actually left yet. Tomorrow is my last day before August)

A slightly more descriptive description would be nice, though.

[Xianzhu, 2016-05-26 18:09:22]

Description was changed from

==========
Fix LayoutObject::paintingLayer() about multicol spanner

BUG=611609
TEST=LayoutObjectTest.PaintingLayerOfOverflowClipLayerUnderColumnSpanAll
==========

to

==========
Fix LayoutObject::paintingLayer() about multicol spanner

This fixes LayoutObject::paintLayer() for the following case:
<div style="columns: 3">
  <div style="column-span: all">
    <div style="overflow: hidden"></div>
  </div>
</div>

The inner div has a non-self-painting layer whose parent layer is the
multicol flow thread layer because layout tree and layer tree structure
follows the dom structure. However, the multicol flow thread layer is
not the actual painting layer but the column container layer is.

When looking for the painting layer, we need to follow the layout tree
instead of the layer tree and skip to the multicol container when we see
a spanner.

BUG=611609
TEST=LayoutObjectTest.PaintingLayerOfOverflowClipLayerUnderColumnSpanAll
==========

[Xianzhu, 2016-05-26 18:09:34]

On 2016/05/26 17:57:32, mstensho (back 2016-08-08) wrote:
> lgtm
> 
> (I haven't actually left yet. Tomorrow is my last day before August)
> 
> A slightly more descriptive description would be nice, though.

Done.

[Xianzhu, 2016-05-26 18:09:49]

The CQ bit was checked by wangxianzhu@chromium.org

[commit-bot: I haz the power, 2016-05-26 18:10:26]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2014093002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2014093002/1

[commit-bot: I haz the power, 2016-05-26 19:45:50]

Description was changed from

==========
Fix LayoutObject::paintingLayer() about multicol spanner

This fixes LayoutObject::paintLayer() for the following case:
<div style="columns: 3">
  <div style="column-span: all">
    <div style="overflow: hidden"></div>
  </div>
</div>

The inner div has a non-self-painting layer whose parent layer is the
multicol flow thread layer because layout tree and layer tree structure
follows the dom structure. However, the multicol flow thread layer is
not the actual painting layer but the column container layer is.

When looking for the painting layer, we need to follow the layout tree
instead of the layer tree and skip to the multicol container when we see
a spanner.

BUG=611609
TEST=LayoutObjectTest.PaintingLayerOfOverflowClipLayerUnderColumnSpanAll
==========

to

==========
Fix LayoutObject::paintingLayer() about multicol spanner

This fixes LayoutObject::paintLayer() for the following case:
<div style="columns: 3">
  <div style="column-span: all">
    <div style="overflow: hidden"></div>
  </div>
</div>

The inner div has a non-self-painting layer whose parent layer is the
multicol flow thread layer because layout tree and layer tree structure
follows the dom structure. However, the multicol flow thread layer is
not the actual painting layer but the column container layer is.

When looking for the painting layer, we need to follow the layout tree
instead of the layer tree and skip to the multicol container when we see
a spanner.

BUG=611609
TEST=LayoutObjectTest.PaintingLayerOfOverflowClipLayerUnderColumnSpanAll
==========

[commit-bot: I haz the power, 2016-05-26 19:45:51]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-26 19:47:51]

Description was changed from

==========
Fix LayoutObject::paintingLayer() about multicol spanner

This fixes LayoutObject::paintLayer() for the following case:
<div style="columns: 3">
  <div style="column-span: all">
    <div style="overflow: hidden"></div>
  </div>
</div>

The inner div has a non-self-painting layer whose parent layer is the
multicol flow thread layer because layout tree and layer tree structure
follows the dom structure. However, the multicol flow thread layer is
not the actual painting layer but the column container layer is.

When looking for the painting layer, we need to follow the layout tree
instead of the layer tree and skip to the multicol container when we see
a spanner.

BUG=611609
TEST=LayoutObjectTest.PaintingLayerOfOverflowClipLayerUnderColumnSpanAll
==========

to

==========
Fix LayoutObject::paintingLayer() about multicol spanner

This fixes LayoutObject::paintLayer() for the following case:
<div style="columns: 3">
  <div style="column-span: all">
    <div style="overflow: hidden"></div>
  </div>
</div>

The inner div has a non-self-painting layer whose parent layer is the
multicol flow thread layer because layout tree and layer tree structure
follows the dom structure. However, the multicol flow thread layer is
not the actual painting layer but the column container layer is.

When looking for the painting layer, we need to follow the layout tree
instead of the layer tree and skip to the multicol container when we see
a spanner.

BUG=611609
TEST=LayoutObjectTest.PaintingLayerOfOverflowClipLayerUnderColumnSpanAll

Committed: https://crrev.com/db39a0e1882876a8c833821caf0544e8155eaa72
Cr-Commit-Position: refs/heads/master@{#396259}
==========

[commit-bot: I haz the power, 2016-05-26 19:47:53]

Patchset 1 (id:??) landed as
https://crrev.com/db39a0e1882876a8c833821caf0544e8155eaa72
Cr-Commit-Position: refs/heads/master@{#396259}