Add more specialized fragment builders

src/gpu/effects/GrXfermodeFragmentProcessor.cpp

Index: src/gpu/effects/GrXfermodeFragmentProcessor.cpp
diff --git a/src/gpu/effects/GrXfermodeFragmentProcessor.cpp b/src/gpu/effects/GrXfermodeFragmentProcessor.cpp
index 7a358d6ef5f2e4b6ff1d82704e4c26717038a308..a881999e0ac4f48bc61f581fd47c8277079072ba 100644
--- a/src/gpu/effects/GrXfermodeFragmentProcessor.cpp
+++ b/src/gpu/effects/GrXfermodeFragmentProcessor.cpp
@@ -87,7 +87,7 @@ GrGLSLFragmentProcessor* ComposeTwoFragmentProcessor::onCreateGLSLInstance() con
 
 void GLComposeTwoFragmentProcessor::emitCode(EmitArgs& args) {
 
-    GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
+    GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
     const ComposeTwoFragmentProcessor& cs = args.fFp.cast<ComposeTwoFragmentProcessor>();
 
     const char* inputColor = nullptr;
@@ -228,7 +228,7 @@ private:
 class GLComposeOneFragmentProcessor : public GrGLSLFragmentProcessor {
 public:
     void emitCode(EmitArgs& args) override {
-        GrGLSLFragmentBuilder* fragBuilder = args.fFragBuilder;
+        GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
         SkXfermode::Mode mode = args.fFp.cast<ComposeOneFragmentProcessor>().mode();
         ComposeOneFragmentProcessor::Child child =
             args.fFp.cast<ComposeOneFragmentProcessor>().child();