Added mangleString member and onBefore*, onAfter* functions to GrGLFragmentShaderBuilder

src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp

Index: src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
diff --git a/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
index a7a35e3676f41c4eaf1657864c4238a1a7a8d0a3..20bb3a389341a5bf1f614587d042a8ca3e0d91cf 100644
--- a/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
+++ b/src/gpu/gl/builders/GrGLFragmentShaderBuilder.cpp
@@ -300,3 +300,15 @@ void GrGLFragmentShaderBuilder::addVarying(GrGLVarying* v, GrSLPrecision fsPrec)
     }
     fInputs.push_back().set(v->fType, GrGLShaderVar::kVaryingIn_TypeModifier, v->fFsIn, fsPrec);
 }
+
+void GrGLFragmentBuilder::onBeforeChildProcEmitCode() {
+    fSubstageIndices.back()++;
+    fSubstageIndices.push_back(0);
+    fMangleString.append(this->getMangleStringThisLevel());
+}
+
+void GrGLFragmentBuilder::onAfterChildProcEmitCode() {
+    fSubstageIndices.pop_back();
+    int removeAt = fMangleString.findLastOf('_');
+    fMangleString.remove(removeAt, fMangleString.size() - removeAt);
+}