Make XPFragmentBuilder only Builder with access to DstCopy.

src/effects/SkColorCubeFilter.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorCubeFilter.h"
 #include "SkColorPriv.h"
 #include "SkOnce.h"
@@ skipping 277 matching lines @@
 
     const char* nonZeroAlpha = "nonZeroAlpha";
     const char* unPMColor = "unPMColor";
     const char* cubeIdx = "cubeIdx";
     const char* cCoords1 = "cCoords1";
     const char* cCoords2 = "cCoords2";
 
     // Note: if implemented using texture3D in OpenGL ES older than OpenGL ES 3.0,
     //       the shader might need "#extension GL_OES_texture_3D : enable".
 
-    GrGLFPFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
+    GrGLFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
 
     // Unpremultiply color
     fsBuilder->codeAppendf("\tfloat %s = max(%s.a, 0.00001);\n", nonZeroAlpha, inputColor);
     fsBuilder->codeAppendf("\tvec4 %s = vec4(%s.rgb / %s, %s);\n",
                            unPMColor, inputColor, nonZeroAlpha, nonZeroAlpha);
 
     // Fit input color into the cube.
     fsBuilder->codeAppendf(
         "vec3 %s = vec3(%s.rg * vec2((%s - 1.0) * %s) + vec2(0.5 * %s), %s.b * (%s - 1.0));\n",
         cubeIdx, unPMColor, colorCubeSizeUni, colorCubeInvSizeUni, colorCubeInvSizeUni,
@@ skipping 53 matching lines @@
     GrFragmentProcessor* frag = textureCube ? GrColorCubeEffect::Create(textureCube) : NULL;
     if (frag) {
         if (array) {
             *array->append() = frag;
         }
         return true;
     }
     return false;
 }
 #endif