Added tree structure to GrGLFragmentProcessor, i.e. GL instances

src/effects/gradients/SkRadialGradient.cpp

Index: src/effects/gradients/SkRadialGradient.cpp
diff --git a/src/effects/gradients/SkRadialGradient.cpp b/src/effects/gradients/SkRadialGradient.cpp
index 4f97e268d505db39e69d366c7edda2986ba6911d..4ff635ab473e46d8d5b0953225f39cf48d8aa0ab 100644
--- a/src/effects/gradients/SkRadialGradient.cpp
+++ b/src/effects/gradients/SkRadialGradient.cpp
@@ -468,10 +468,6 @@ public:
 
     const char* name() const override { return "Radial Gradient"; }
 
-    GrGLFragmentProcessor* createGLInstance() const override {
-        return SkNEW_ARGS(GrGLRadialGradient, (*this));
-    }
-
 private:
     GrRadialGradient(GrContext* ctx,
                      GrProcessorDataManager* procDataManager,
@@ -482,6 +478,10 @@ private:
         this->initClassID<GrRadialGradient>();
     }
 
+    GrGLFragmentProcessor* onCreateGLInstance() const override {
+        return SkNEW_ARGS(GrGLRadialGradient, (*this));
+    }
+
     virtual void onGetGLProcessorKey(const GrGLSLCaps& caps,
                                      GrProcessorKeyBuilder* b) const override {
         GrGLRadialGradient::GenKey(*this, caps, b);