Add support for enabling DirectWrite for font rendering in Chrome UI.

This is enabled if Harf Buzz text rendering is enabled and if the enable-directwrite-for-ui switch
is passed in the command line.

To enable DirectWrite we use the SkFontMgr_New_DirectWrite function in skia which sets up skia to use
DirectWrite for font rendering. This is done once during startup.

BUG=389649

Review URL: https://codereview.chromium.org/655613003

Cr-Commit-Position: refs/heads/master@{#299612}
3 files changed