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

src/effects/gradients/SkSweepGradient.cpp

Index: src/effects/gradients/SkSweepGradient.cpp
diff --git a/src/effects/gradients/SkSweepGradient.cpp b/src/effects/gradients/SkSweepGradient.cpp
index 4936d31505f5cb9097540cc48b338e3e18e65c91..18816904949255f455c6ee6600e67b4541edfe6e 100644
--- a/src/effects/gradients/SkSweepGradient.cpp
+++ b/src/effects/gradients/SkSweepGradient.cpp
@@ -214,10 +214,6 @@ public:
 
     const char* name() const override { return "Sweep Gradient"; }
 
-    GrGLFragmentProcessor* createGLInstance() const override {
-        return SkNEW_ARGS(GrGLSweepGradient, (*this));
-    }
-
 private:
     GrSweepGradient(GrContext* ctx,
                     GrProcessorDataManager* procDataManager,
@@ -227,6 +223,10 @@ private:
         this->initClassID<GrSweepGradient>();
     }
 
+    GrGLFragmentProcessor* onCreateGLInstance() const override {
+        return SkNEW_ARGS(GrGLSweepGradient, (*this));
+    }
+
     virtual void onGetGLProcessorKey(const GrGLSLCaps& caps,
                                      GrProcessorKeyBuilder* b) const override {
         GrGLSweepGradient::GenKey(*this, caps, b);