Merge most of it into RenderBox. Only RenderBoxes can have
layers now. This also meant a bit of code could be cleaned up
since some virtuals (e.g. updateFromStyle) are no longer needed
since they're only called on RenderBoxes.
collectSelfPaintingLayers is the only bit that's moved into
RenderBoxModelObject instead of RenderBox. That's because we
need to be able to recurse down into RenderInlines since they
may contain RenderBoxes that have selfPaintingLayers.
R=abarth@chromium.org
Review URL: https://codereview.chromium.org/953673002
This caused us to lose our gn check certification. :(
Turns out gn check was just ignoring all the header
paths it didn't understand and so gn check passing
for sky wasn't meaning much. I tried to straighten
out some of the mess in this CL, but its going to take
several more rounds of massaging before gn check
passes again. On the bright side (almost) all of
our headers are absolute now. Turns out my script
(attached to the bug) didn't notice ../ includes
but I'll fix that in the next patch.
R=abarth@chromium.org
BUG=435361
Review URL: https://codereview.chromium.org/746023002
