add a SkFontMgr to DM that returns portable fonts

Controlled by --[no]nativeFonts, and still defaults to native fonts.

Change-Id: Ib2879e69fadb63ddb5a17a7e4ae227941893b8cf
Reviewed-on: https://skia-review.googlesource.com/67806
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
5 files changed