combine setRectFan and mapRect

src/gpu/GrQuad.h

Index: src/gpu/GrQuad.h
diff --git a/src/gpu/GrQuad.h b/src/gpu/GrQuad.h
index 9a8d1f3a4a37a1d421b83ceb52700ce593a0391d..3a202c61cb47da623493dd4da242fc3d01a61c47 100644
--- a/src/gpu/GrQuad.h
+++ b/src/gpu/GrQuad.h
@@ -10,6 +10,7 @@
 
 #include "SkPoint.h"
 #include "SkMatrix.h"
+#include "SkMatrixPriv.h"
 
 /**
  * GrQuad is a collection of 4 points which can be used to represent an arbitrary quadrilateral
@@ -35,8 +36,7 @@ public:
     }
 
     void setFromMappedRect(const SkRect& rect, const SkMatrix& matrix) {
-        this->set(rect);
-        matrix.mapPoints(fPoints, kNumPoints);
+        SkMatrixPriv::SetMappedRectFan(matrix, rect, fPoints);
     }
 
     const GrQuad& operator=(const GrQuad& that) {