Add nativeFonts flag to Viewer.

This moves DMFontMgr and several related files which are tightly related
to fonts into tools/fonts, moves some flags around to prevent
duplication, and adds the nativeFonts handling to Viewer.

Change-Id: Id1bdad708a6b74319ac5ac9adfe21025db4ca0b2
Reviewed-on: https://skia-review.googlesource.com/108904
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
23 files changed