Make bicubic FP factories return const FPs

src/gpu/effects/GrBicubicEffect.h

Index: src/gpu/effects/GrBicubicEffect.h
diff --git a/src/gpu/effects/GrBicubicEffect.h b/src/gpu/effects/GrBicubicEffect.h
index 9167b9cc6f6e4ad384a34a27cc7f6a22100f96a8..9f9e20dbd165ef99b8bb3cb58e8e2f98986141a4 100644
--- a/src/gpu/effects/GrBicubicEffect.h
+++ b/src/gpu/effects/GrBicubicEffect.h
@@ -32,8 +32,8 @@ public:
     /**
      * Create a simple filter effect with custom bicubic coefficients and optional domain.
      */
-    static GrFragmentProcessor* Create(GrTexture* tex, const SkScalar coefficients[16],
-                                       const SkRect* domain = nullptr) {
+    static const GrFragmentProcessor* Create(GrTexture* tex, const SkScalar coefficients[16],
+                                             const SkRect* domain = nullptr) {
         if (nullptr == domain) {
             static const SkShader::TileMode kTileModes[] = { SkShader::kClamp_TileMode,
                                                              SkShader::kClamp_TileMode };
@@ -48,8 +48,8 @@ public:
     /**
      * Create a Mitchell filter effect with specified texture matrix and x/y tile modes.
      */
-    static GrFragmentProcessor* Create(GrTexture* tex, const SkMatrix& matrix,
-                                       SkShader::TileMode tileModes[2]) {
+    static const GrFragmentProcessor* Create(GrTexture* tex, const SkMatrix& matrix,
+                                             SkShader::TileMode tileModes[2]) {
         return Create(tex, gMitchellCoefficients, matrix, tileModes);
     }
 
@@ -57,17 +57,17 @@ public:
      * Create a filter effect with custom bicubic coefficients, the texture matrix, and the x/y
      * tilemodes.
      */
-    static GrFragmentProcessor* Create(GrTexture* tex, const SkScalar coefficients[16],
-                                       const SkMatrix& matrix,
-                                       const SkShader::TileMode tileModes[2]) {
+    static const GrFragmentProcessor* Create(GrTexture* tex, const SkScalar coefficients[16],
+                                             const SkMatrix& matrix,
+                                             const SkShader::TileMode tileModes[2]) {
         return new GrBicubicEffect(tex, coefficients, matrix, tileModes);
     }
 
     /**
      * Create a Mitchell filter effect with a texture matrix and a domain.
      */
-    static GrFragmentProcessor* Create(GrTexture* tex, const SkMatrix& matrix,
-                                       const SkRect& domain) {
+    static const GrFragmentProcessor* Create(GrTexture* tex, const SkMatrix& matrix,
+                                             const SkRect& domain) {
         return new GrBicubicEffect(tex, gMitchellCoefficients, matrix, domain);
     }