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
Review URL: https://codereview.chromium.org/899753003
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
