Remove redundant calls to PaintFlags::setAntiAlias

In most of these cases we use GraphicsContext::FillFlags - which
will already have the value returned by GraphicsContext::ShouldAntialias
set.
In the remaining case we copy the flag from the PaintFlags which
we made a copy of already.

Change-Id: I25fe7f578017c215cd8950aa3a74b2664bf29615
Reviewed-on: https://chromium-review.googlesource.com/c/1403456
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#621263}
3 files changed