Remove compositing chicken/egg issues in RenderObject::adjustStyleDifference

Previously, this could would query compositing state to determine what sort of
style difference a translate or similar CSS change ought to be treated as.
Instead of querying the compositing state, this CL moves us to just using the
direct reasons for compositing. In the comon case, when we have a composited
layer, the direct reasons for compositing will contain that information. In the
uncommon case, where we have a compositing layer for another reason, we'll end
up doing some extra work.

This CL resolves the chicken/egg problems in this function because we can
compute the direct compositing reasons incrementally without needing to
recompute the indirect reasons for compositing (which involve global
information about the page, e.g., about the positions of various elements).

R=esprehn@chromium.org
BUG=339848

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=167141

Review URL: https://codereview.chromium.org/165563002

git-svn-id: svn://svn.chromium.org/blink/trunk@167441 bbb929c8-8fbe-4397-9dbb-9b2b20218538