Make XPFragmentBuilder only Builder with access to DstCopy.

src/effects/SkMagnifierImageFilter.cpp

 /*
  * Copyright 2012 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkMagnifierImageFilter.h"
 #include "SkColorPriv.h"
@@ skipping 133 matching lines @@
         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvZoom");
     fInvInsetVar = builder->addUniform(
         GrGLProgramBuilder::kFragment_Visibility |
         GrGLProgramBuilder::kVertex_Visibility,
         kVec2f_GrSLType, kDefault_GrSLPrecision, "InvInset");
     fBoundsVar = builder->addUniform(
         GrGLProgramBuilder::kFragment_Visibility |
         GrGLProgramBuilder::kVertex_Visibility,
         kVec4f_GrSLType, kDefault_GrSLPrecision, "Bounds");
 
-    GrGLFPFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
+    GrGLFragmentBuilder* fsBuilder = builder->getFragmentShaderBuilder();
     SkString coords2D = fsBuilder->ensureFSCoords2D(coords, 0);
     fsBuilder->codeAppendf("\t\tvec2 coord = %s;\n", coords2D.c_str());
     fsBuilder->codeAppendf("\t\tvec2 zoom_coord = %s + %s * %s;\n",
                            builder->getUniformCStr(fOffsetVar),
                            coords2D.c_str(),
                            builder->getUniformCStr(fInvZoomVar));
     const char* bounds = builder->getUniformCStr(fBoundsVar);
     fsBuilder->codeAppendf("\t\tvec2 delta = (coord - %s.xy) * %s.zw;\n", bounds, bounds);
     fsBuilder->codeAppendf("\t\tdelta = min(delta, vec2(1.0, 1.0) - delta);\n");
     fsBuilder->codeAppendf("\t\tdelta = delta * %s;\n", builder->getUniformCStr(fInvInsetVar));
@@ skipping 220 matching lines @@
 
 #ifndef SK_IGNORE_TO_STRING
 void SkMagnifierImageFilter::toString(SkString* str) const {
     str->appendf("SkMagnifierImageFilter: (");
     str->appendf("src: (%f,%f,%f,%f) ",
                  fSrcRect.fLeft, fSrcRect.fTop, fSrcRect.fRight, fSrcRect.fBottom);
     str->appendf("inset: %f", fInset);
     str->append(")");
 }
 #endif