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

src/gpu/effects/GrCustomXfermodePriv.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrCustomXfermodePriv_DEFINED
 #define GrCustomXfermodePriv_DEFINED
 
@@ skipping 11 matching lines @@
 class GrTexture;
 
 ///////////////////////////////////////////////////////////////////////////////
 // Fragment Processor
 ///////////////////////////////////////////////////////////////////////////////
 
 class GrCustomXferFP : public GrFragmentProcessor {
 public:
     GrCustomXferFP(GrProcessorDataManager*, SkXfermode::Mode mode, GrTexture* background);
 
-    GrGLFragmentProcessor* createGLInstance() const override;
-
     const char* name() const override { return "Custom Xfermode"; }
 
     SkXfermode::Mode mode() const { return fMode; }
     const GrTextureAccess&  backgroundAccess() const { return fBackgroundAccess; }
 
 private:
+    GrGLFragmentProcessor* onCreateGLInstance() const override;
+
     void onGetGLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const override;
 
     bool onIsEqual(const GrFragmentProcessor& other) const override; 
 
     void onComputeInvariantOutput(GrInvariantOutput* inout) const override;
 
     GR_DECLARE_FRAGMENT_PROCESSOR_TEST;
 
     SkXfermode::Mode fMode;
     GrCoordTransform fBackgroundTransform;
@@ skipping 36 matching lines @@
 
     GR_DECLARE_XP_FACTORY_TEST;
 
     SkXfermode::Mode fMode;
     GrBlendEquation  fHWBlendEquation;
 
     typedef GrXPFactory INHERITED;
 };
 #endif