Set resScale on stroker when stroking path on gpu.

include/core/SkStrokeRec.h

Index: include/core/SkStrokeRec.h
diff --git a/include/core/SkStrokeRec.h b/include/core/SkStrokeRec.h
index 4858fce28edbc0ec44c64fba00b76ee7a0ad9087..00b1fc1fca6d0d1479e3d3e4e2f4d8ce760256d7 100644
--- a/include/core/SkStrokeRec.h
+++ b/include/core/SkStrokeRec.h
@@ -64,6 +64,11 @@ public:
         fMiterLimit = miterLimit;
     }
 
+    void setResScale(SkScalar rs) {
+        SkASSERT(rs > 0 && SkScalarIsFinite(rs));
+        fResScale = rs;
+    }
+
     /**
      *  Returns true if this specifes any thick stroking, i.e. applyToPath()
      *  will return true.