SkAutoRef seems lonely.  Might as well delete it.

(On the other hand, SkAutoUnref is well-used.)

NOTREECHECKS=true

BUG=skia:
R=bungeman@google.com, mtklein@google.com, reed@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/393953004
diff --git a/src/gpu/GrTextStrike.cpp b/src/gpu/GrTextStrike.cpp
index 4079893..46d7a53 100644
--- a/src/gpu/GrTextStrike.cpp
+++ b/src/gpu/GrTextStrike.cpp
@@ -293,7 +293,7 @@
     SkASSERT(fCache.contains(glyph));
     SkASSERT(NULL == glyph->fPlot);
 
-    SkAutoRef ar(scaler);
+    SkAutoUnref ar(SkSafeRef(scaler));
 
     int bytesPerPixel = GrMaskFormatBytesPerPixel(fMaskFormat);