[DirectWrite] Change minimum antialiased size for SimSun to 11px

Change the minimum size at which antialiasing is enabled for the SimSun
font to 11px. This ensures higher quality rendering at sizes where the
font is legible with GDI-style AA.

BUG=384091
R=cpu@chromium.org

Review URL: https://codereview.chromium.org/348603005

git-svn-id: svn://svn.chromium.org/blink/trunk@177233 bbb929c8-8fbe-4397-9dbb-9b2b20218538