Make XPFragmentBuilder only Builder with access to DstCopy.

src/gpu/effects/GrBitmapTextGeoProc.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrBitmapTextGeoProc.h"
 #include "GrFontAtlasSizes.h"
 #include "GrInvariantOutput.h"
@@ skipping 42 matching lines @@
         this->setupColorPassThrough(pb, local.fInputColorType, args.fOutputColor, cte.inColor(),
                                     &fColorUniform);
 
         // Setup position
         this->setupPosition(pb, gpArgs, cte.inPosition()->fName, cte.viewMatrix());
 
         // emit transforms
         this->emitTransforms(args.fPB, gpArgs->fPositionVar, cte.inPosition()->fName,
                              cte.localMatrix(), args.fTransformsIn, args.fTransformsOut);
 
-        GrGLGPFragmentBuilder* fsBuilder = pb->getFragmentShaderBuilder();
+        GrGLFragmentBuilder* fsBuilder = pb->getFragmentShaderBuilder();
         if (cte.maskFormat() == kARGB_GrMaskFormat) {
             fsBuilder->codeAppendf("%s = ", args.fOutputColor);
             fsBuilder->appendTextureLookupAndModulate(args.fOutputColor,
                                                       args.fSamplers[0],
                                                       v.fsIn(),
                                                       kVec2f_GrSLType);
             fsBuilder->codeAppend(";");
             fsBuilder->codeAppendf("%s = vec4(1);", args.fOutputCoverage);
         } else {
             fsBuilder->codeAppendf("%s = ", args.fOutputCoverage);
@@ skipping 153 matching lines @@
             break;
         case 2:
             format = kARGB_GrMaskFormat;
             break;
     }
 
     return GrBitmapTextGeoProc::Create(GrRandomColor(random), textures[texIdx], params,
                                        format, random->nextBool(),
                                        GrTest::TestMatrix(random));
 }