Support pixel antialising in DirectWrite.

DirectWrite2 supports pixel antialiasing and rendering without hinting.
To maintain the infered size based decisions of the previous rendering,
only use the new renderer when it is needed.

BUG=skia:5416

Change-Id: Ia87fdf8fc91dc7ff0f0ce4284c90a5d79045308f
Reviewed-on: https://skia-review.googlesource.com/9805
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
4 files changed