Trivial clean up: Remove a couple of unneeded RenderStyle friends

Review URL: https://codereview.chromium.org/363613002

git-svn-id: svn://svn.chromium.org/blink/trunk@177356 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make squashing match other composited layers' behavior for pagination and opaque background.

BUG=384520

Review URL: https://codereview.chromium.org/366553002

git-svn-id: svn://svn.chromium.org/blink/trunk@177357 bbb929c8-8fbe-4397-9dbb-9b2b20218538