Get correct text metrics for distance fields, and fix dropouts due to thin features.

BUG=skia:2173
R=robertphillips@google.com, reed@google.com

Author: jvanverth@google.com

Review URL: https://codereview.chromium.org/200423003

git-svn-id: http://skia.googlecode.com/svn/trunk@13815 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrDistanceFieldTextContext.cpp b/src/gpu/GrDistanceFieldTextContext.cpp
index 03d09a0..2163e64 100755
--- a/src/gpu/GrDistanceFieldTextContext.cpp
+++ b/src/gpu/GrDistanceFieldTextContext.cpp
@@ -308,7 +308,7 @@
     fSkPaint.setTextSize(SkIntToScalar(kBaseDFFontSize));
     fSkPaint.setLCDRenderText(false);
     fSkPaint.setAutohinted(false);
-    fSkPaint.setSubpixelText(false);
+    fSkPaint.setSubpixelText(true);
 }
 
 inline void GrDistanceFieldTextContext::finish() {