Improve SkTestFontMgr.

This moves the portable typefaces into the portable font manager.

Change-Id: Id25e8f0b90f99c82d09cfb3ef136bda8c7728ee9
Reviewed-on: https://skia-review.googlesource.com/140351
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
diff --git a/gm/fontmgr.cpp b/gm/fontmgr.cpp
index c3fff70..e544a3e 100644
--- a/gm/fontmgr.cpp
+++ b/gm/fontmgr.cpp
@@ -180,7 +180,7 @@
         paint.setTextSize(17);
 
         const char* gNames[] = {
-            "Helvetica Neue", "Arial"
+            "Helvetica Neue", "Arial", "sans"
         };
 
         sk_sp<SkFontStyleSet> fset;