[RootLayerScrolls] No more absolute coordinates

"Absolute" coordinates were a shim to ease the RLS transition. Get rid
of them in favor of "Frame" and "Document" coordinates.

BUG=823365
R=skobes@chromium.org,bokan@chromium.org

Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_slimming_paint_v2;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: Id82f7908c32b2b529a2259bb5e18339a5568458a
Reviewed-on: https://chromium-review.googlesource.com/1100540
Commit-Queue: Stefan Zager <szager@chromium.org>
Reviewed-by: Steve Kobes <skobes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567329}
24 files changed