Make XPFragmentBuilder only Builder with access to DstCopy.

src/gpu/effects/GrMatrixConvolutionEffect.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 "GrMatrixConvolutionEffect.h"
 #include "gl/GrGLProcessor.h"
 #include "gl/GrGLSL.h"
 #include "gl/GrGLTexture.h"
@@ skipping 56 matching lines @@
                                    kFloat_GrSLType, kDefault_GrSLPrecision, "Bias");
 
     const char* kernelOffset = builder->getUniformCStr(fKernelOffsetUni);
     const char* imgInc = builder->getUniformCStr(fImageIncrementUni);
     const char* kernel = builder->getUniformCStr(fKernelUni);
     const char* gain = builder->getUniformCStr(fGainUni);
     const char* bias = builder->getUniformCStr(fBiasUni);
     int kWidth = fKernelSize.width();
     int kHeight = fKernelSize.height();
 
-    GrGLFPFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
+    GrGLFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
     SkString coords2D = fsBuilder->ensureFSCoords2D(coords, 0);
     fsBuilder->codeAppend("vec4 sum = vec4(0, 0, 0, 0);");
     fsBuilder->codeAppendf("vec2 coord = %s - %s * %s;", coords2D.c_str(), kernelOffset,
                            imgInc);
     fsBuilder->codeAppend("vec4 c;");
 
     for (int y = 0; y < kHeight; y++) {
         for (int x = 0; x < kWidth; x++) {
             GrGLShaderBuilder::ShaderBlock block(fsBuilder);
             fsBuilder->codeAppendf("float k = %s[%d * %d + %d];", kernel, y, kWidth, x);
@@ skipping 175 matching lines @@
     return GrMatrixConvolutionEffect::Create(textures[texIdx],
                                              bounds,
                                              kernelSize,
                                              kernel.get(),
                                              gain,
                                              bias,
                                              kernelOffset,
                                              tileMode,
                                              convolveAlpha);
 }