[blink] Relax transformed rasterization policy

Transformed rasterization were enabled only for layers that are
composited for overlapping. This CL broadens the criteria to include
every layers that don't have a direct compositing reason.

This will improve draw quality on affected layers, but may also
slightly increase raster costs.

BUG=521364

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: I1f52ba1b6ca77dea0d60a6adc4483ea255420746
Reviewed-on: https://chromium-review.googlesource.com/526480
Reviewed-by: Chris harrelson <chrishtr@chromium.org>
Commit-Queue: Tien-Ren Chen <trchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#479548}
7 files changed