some utils for rect and matrix

include/gpu/GrCoordTransform.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrCoordTransform_DEFINED
 #define GrCoordTransform_DEFINED
 
@@ skipping 107 matching lines @@
     GrCoordSet sourceCoords() const { return fSourceCoords; }
     const SkMatrix& getMatrix() const { return fMatrix; }
     bool reverseY() const { return fReverseY; }
     GrSLPrecision precision() const { return fPrecision; }
 
     /** Useful for effects that want to insert a texture matrix that is implied by the texture
         dimensions */
     static inline SkMatrix MakeDivByTextureWHMatrix(const GrTexture* texture) {
         SkASSERT(texture);
         SkMatrix mat;
-        mat.setIDiv(texture->width(), texture->height());
+        (void)mat.setIDiv(texture->width(), texture->height());
         return mat;
     }
 
 private:
     GrCoordSet              fSourceCoords;
     SkMatrix                fMatrix;
     bool                    fReverseY;
     GrSLPrecision           fPrecision;
     typedef SkNoncopyable INHERITED;
 
 #ifdef SK_DEBUG
 public:
     void setInProcessor() const { fInProcessor = true; }
 private:
     mutable bool fInProcessor;
 #endif
 };
 
 #endif