Initial linear gradient 4f impl

src/effects/gradients/SkGradientShaderPriv.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkGradientShaderPriv_DEFINED
 #define SkGradientShaderPriv_DEFINED
 
@@ skipping 203 matching lines @@
     };
 
     // Determines and returns the gradient is a two color gradient, symmetric three color gradient
     // or other (texture gradient). If it is two or symmetric three color, the colors array will
     // also be filled with the gradient colors
     GpuColorType getGpuColorType(SkColor colors[3]) const;
 
     uint32_t getGradFlags() const { return fGradFlags; }
 
 protected:
+    class GradientShaderBase4fContext;
+
     SkGradientShaderBase(SkReadBuffer& );
     void flatten(SkWriteBuffer&) const override;
     SK_TO_STRING_OVERRIDE()
 
     const SkMatrix fPtsToUnit;
     TileMode    fTileMode;
     TileProc    fTileProc;
     int         fColorCount;
     uint8_t     fGradFlags;
 
@@ skipping 221 matching lines @@
     GrGLSLProgramDataManager::UniformHandle fColorStartUni;
     GrGLSLProgramDataManager::UniformHandle fColorMidUni;
     GrGLSLProgramDataManager::UniformHandle fColorEndUni;
 
     typedef GrGLSLFragmentProcessor INHERITED;
 };
 
 #endif
 
 #endif