Walk render tree instead of render layers for paint.

Walk render tree instead of render layers for paint.

This is the first step of getting rid of RenderLayer.
Instead of walking the RenderLayer tree, wall the RenderObject
tree and add any layers encountered to a vector to paint later.

This patch just consolidates and move the code from RenderLayer
to RenderBox and then changes the children painting to
iterate over the vector. Therefore we walk the RenderObject tree.
We still call out to RenderLayer in a bunch of places.
A followup patch will get rid of those.

R=esprehn@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/176c40ab728c5af7e6300629c6eaefeb970b547a

[ojan, 2015-02-05 10:18:08]

ojan@chromium.org changed reviewers:
+ esprehn@chromium.org

[esprehn, 2015-02-05 23:47:00]

You're missing a & all over.

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/In...
File sky/engine/core/rendering/InlineFlowBox.cpp (right):

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/In...
sky/engine/core/rendering/InlineFlowBox.cpp:992: void
InlineFlowBox::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset,
LayoutUnit lineTop, LayoutUnit lineBottom, Vector<RenderBox*> layers)
reference.

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/In...
File sky/engine/core/rendering/InlineTextBox.cpp (right):

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/In...
sky/engine/core/rendering/InlineTextBox.cpp:481: void
InlineTextBox::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset,
LayoutUnit /*lineTop*/, LayoutUnit /*lineBottom*/, Vector<RenderBox*> layers)
Vector<RenderBox*>&, you're making copies all over instead of passing by
reference.

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/Re...
File sky/engine/core/rendering/RenderBox.cpp (right):

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/Re...
sky/engine/core/rendering/RenderBox.cpp:400: if (!opacity())
We could actually do this optimization in the hasSelfPaintingLayer() check,
where we don't even add it to the layers Vector or the children of it.

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/Re...
sky/engine/core/rendering/RenderBox.cpp:426: if (layer()->parent()) {
The root never has a transform, so in a future patch we should remove the
parent() checks and just add an ASSERT() at the top.

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/Re...
sky/engine/core/rendering/RenderBox.cpp:480: if (hasClipPath() && style()) {
The style() null check doesn't make sense, you always have a style.

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/Ro...
File sky/engine/core/rendering/RootInlineBox.cpp (right):

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/Ro...
sky/engine/core/rendering/RootInlineBox.cpp:152: void
RootInlineBox::paintEllipsisBox(PaintInfo& paintInfo, const LayoutPoint&
paintOffset, LayoutUnit lineTop, LayoutUnit lineBottom, Vector<RenderBox*>
layers) const
reference.

[ojan, 2015-02-06 00:28:46]

ptal

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/Re...
File sky/engine/core/rendering/RenderBox.cpp (right):

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/Re...
sky/engine/core/rendering/RenderBox.cpp:400: if (!opacity())
On 2015/02/05 23:47:00, esprehn wrote:
> We could actually do this optimization in the hasSelfPaintingLayer() check,
> where we don't even add it to the layers Vector or the children of it.

Good idea. Added TODO.

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/Re...
sky/engine/core/rendering/RenderBox.cpp:426: if (layer()->parent()) {
On 2015/02/05 23:47:00, esprehn wrote:
> The root never has a transform, so in a future patch we should remove the
> parent() checks and just add an ASSERT() at the top.

TODOs added.

https://codereview.chromium.org/899753003/diff/1/sky/engine/core/rendering/Re...
sky/engine/core/rendering/RenderBox.cpp:480: if (hasClipPath() && style()) {
On 2015/02/05 23:47:00, esprehn wrote:
> The style() null check doesn't make sense, you always have a style.

Yup. I had that thought too, but wanted to minimize changes in this patch. Added
a TODO.

[esprehn, 2015-02-06 00:31:00]

lgtm

[ojan, 2015-02-06 00:39:26]

Committed patchset #2 (id:20001) manually as
176c40ab728c5af7e6300629c6eaefeb970b547a (presubmit successful).