Toggle subpixel text on windows based on font manager

Toggle the subpixel text flag based on the type of font manager
actually used (DirectWrite or GDI) rather than on the directWrite
runtime enabled feature as GDI will be used even if the feature is
enabled on older versions of Windows.

BUG=290411
R=dglazkov@chromium.org

Review URL: https://codereview.chromium.org/97393002

git-svn-id: svn://svn.chromium.org/blink/trunk@162930 bbb929c8-8fbe-4397-9dbb-9b2b20218538