Isolate VertexBuilder from GrGLShaderBuilder

src/effects/gradients/SkTwoPointConicalGradient.cpp

Index: src/effects/gradients/SkTwoPointConicalGradient.cpp
diff --git a/src/effects/gradients/SkTwoPointConicalGradient.cpp b/src/effects/gradients/SkTwoPointConicalGradient.cpp
index 5e0c4b892b472f67e81b3685a2d0099bb531ffe5..cf9cb98a276f66e52925518a53069f548208f993 100644
--- a/src/effects/gradients/SkTwoPointConicalGradient.cpp
+++ b/src/effects/gradients/SkTwoPointConicalGradient.cpp
@@ -506,9 +506,11 @@ void GrGLConical2Gradient::emitCode(GrGLShaderBuilder* builder,
 
     // For radial gradients without perspective we can pass the linear
     // part of the quadratic as a varying.
-    if (kVec2f_GrSLType == coordsVaryingType) {
-        builder->addVarying(kFloat_GrSLType, "Conical2BCoeff",
-                            &fVSVaryingName, &fFSVaryingName);
+    GrGLShaderBuilder::VertexBuilder* vertexBuilder =
+        (kVec2f_GrSLType == coordsVaryingType) ? builder->getVertexBuilder() : NULL;
+    if (NULL != vertexBuilder) {
+        vertexBuilder->addVarying(kFloat_GrSLType, "Conical2BCoeff",
+                                     &fVSVaryingName, &fFSVaryingName);
     }
 
     // VS
@@ -522,11 +524,11 @@ void GrGLConical2Gradient::emitCode(GrGLShaderBuilder* builder,
 
         // For radial gradients without perspective we can pass the linear
         // part of the quadratic as a varying.
-        if (kVec2f_GrSLType == coordsVaryingType) {
+        if (NULL != vertexBuilder) {
             // r2Var = -2 * (r2Parm[2] * varCoord.x - r2Param[3] * r2Param[5])
-            builder->vsCodeAppendf("\t%s = -2.0 * (%s * %s.x + %s * %s);\n",
-                                   fVSVaryingName, p2.c_str(),
-                                   vsCoordsVarying.c_str(), p3.c_str(), p5.c_str());
+            vertexBuilder->vsCodeAppendf("\t%s = -2.0 * (%s * %s.x + %s * %s);\n",
+                                            fVSVaryingName, p2.c_str(),
+                                            vsCoordsVarying.c_str(), p3.c_str(), p5.c_str());
         }
     }
 
@@ -557,7 +559,7 @@ void GrGLConical2Gradient::emitCode(GrGLShaderBuilder* builder,
         // If we we're able to interpolate the linear component,
         // bVar is the varying; otherwise compute it
         SkString bVar;
-        if (kVec2f_GrSLType == coordsVaryingType) {
+        if (NULL != vertexBuilder) {
             bVar = fFSVaryingName;
         } else {
             bVar = "b";