4f gradient interval builder cleanup

src/effects/gradients/Sk4fGradientBase.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef Sk4fGradientBase_DEFINED
 #define Sk4fGradientBase_DEFINED
 
@@ skipping 37 matching lines @@
     SkMatrix                     fDstToPos;
     SkMatrix::MapXYProc          fDstToPosProc;
     uint8_t                      fDstToPosClass;
     uint8_t                      fFlags;
     bool                         fDither;
     bool                         fColorsArePremul;
 
 private:
     using INHERITED = SkShader::Context;
 
+    void addMirrorIntervals(const SkGradientShaderBase&, const Sk4f& componentScale,
+                            bool dx_is_pos);
+
     mutable const Interval*      fCachedInterval;
 };
 
 #endif // Sk4fGradientBase_DEFINED