Add more specialized fragment builders

src/effects/SkAvoidXfermode.cpp

 /*
  * Copyright 2006 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 "SkAvoidXfermode.h"
 #include "SkColorPriv.h"
 #include "SkReadBuffer.h"
@@ skipping 254 matching lines @@
     if (srcCoverage) {
         fragBuilder->codeAppendf("%s *= %s;", kCoverageName, srcCoverage);
     }
 }
 
 class GLAvoidFP : public GrGLSLFragmentProcessor {
 public:
     void emitCode(EmitArgs& args) override {
         const AvoidFP& avoid = args.fFp.cast<AvoidFP>();
 
-        GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
+        GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
         SkString dstColor("dstColor");
         this->emitChild(0, nullptr, &dstColor, args);
 
         fColorAndTolUni = args.fUniformHandler->addUniform(
                                                  kFragment_GrShaderFlag,
                                                  kVec4f_GrSLType, kDefault_GrSLPrecision,
                                                  "colorAndTol");
         const char* kColorAndTolUni = args.fUniformHandler->getUniformCStr(fColorAndTolUni);
 
         const char* kCoverageName = "newCoverage";
@@ skipping 249 matching lines @@
 void SkAvoidXfermode::toString(SkString* str) const {
     str->append("AvoidXfermode: opColor: ");
     str->appendHex(fOpColor);
     str->appendf("tolerance: %d ", fTolerance);
 
     static const char* gModeStrings[] = { "Avoid", "Target" };
 
     str->appendf("mode: %s", gModeStrings[fMode]);
 }
 #endif