Add more specialized fragment builders

src/effects/SkDisplacementMapEffect.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 "SkDisplacementMapEffect.h"
 #include "SkDevice.h"
 #include "SkReadBuffer.h"
@@ skipping 535 matching lines @@
 
     fScaleUni = args.fUniformHandler->addUniform(kFragment_GrShaderFlag,
                                                  kVec2f_GrSLType, kDefault_GrSLPrecision, "Scale");
     const char* scaleUni = args.fUniformHandler->getUniformCStr(fScaleUni);
     const char* dColor = "dColor";
     const char* cCoords = "cCoords";
     const char* nearZero = "1e-6"; // Since 6.10352e−5 is the smallest half float, use
                                    // a number smaller than that to approximate 0, but
                                    // leave room for 32-bit float GPU rounding errors.
 
-    GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
+    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
     fragBuilder->codeAppendf("\t\tvec4 %s = ", dColor);
     fragBuilder->appendTextureLookup(args.fSamplers[0], args.fCoords[0].c_str(),
                                    args.fCoords[0].getType());
     fragBuilder->codeAppend(";\n");
 
     // Unpremultiply the displacement
     fragBuilder->codeAppendf(
         "\t\t%s.rgb = (%s.a < %s) ? vec3(0.0) : clamp(%s.rgb / %s.a, 0.0, 1.0);",
         dColor, dColor, nearZero, dColor, dColor);
     SkString coords2D = fragBuilder->ensureFSCoords2D(args.fCoords, 1);
@@ skipping 63 matching lines @@
                                        const GrGLSLCaps&, GrProcessorKeyBuilder* b) {
     const GrDisplacementMapEffect& displacementMap = proc.cast<GrDisplacementMapEffect>();
 
     uint32_t xKey = displacementMap.xChannelSelector();
     uint32_t yKey = displacementMap.yChannelSelector() << kChannelSelectorKeyBits;
 
     b->add32(xKey | yKey);
 }
 #endif