[SPv175] Enable SlimmingPaintV175 by default

SlimmingPaintV175 enables raster invalidation and paint chunks based
on paint properties. See crbug.com/771643.

Bug: 771643
Change-Id: I5fdbcabc7ca0f2fa8e69ae0fbf5a0077bba46cfe
Reviewed-on: https://chromium-review.googlesource.com/923572
Reviewed-by: Antoine Labour <piman@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537454}
4 files changed