Use MaskFilter to create SDFs for text.

Easy way to store SDFs in the glyph cache.

Change-Id: Ia67e5c8619862bdee6aa3b293e30507d029e3bf1
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/123748
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
diff --git a/gn/gpu.gni b/gn/gpu.gni
index 93e21cb..ac84e45 100644
--- a/gn/gpu.gni
+++ b/gn/gpu.gni
@@ -408,6 +408,8 @@
   "$_src/gpu/text/GrDistanceFieldAdjustTable.h",
   "$_src/gpu/text/GrGlyphCache.cpp",
   "$_src/gpu/text/GrGlyphCache.h",
+  "$_src/gpu/text/GrSDFMaskFilter.cpp",
+  "$_src/gpu/text/GrSDFMaskFilter.h",
   "$_src/gpu/text/GrTextBlobCache.cpp",
   "$_src/gpu/text/GrTextBlobCache.h",
   "$_src/gpu/text/GrTextUtils.cpp",