Extract most of the mutable state of SkShader into a separate Context object.

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 83 matching lines @@
         int                 fCount;
         SkShader::TileMode  fTileMode;
         SkUnitMapper*       fMapper;
         uint32_t            fFlags;
     };
 
 public:
     SkGradientShaderBase(const Descriptor& desc);
     virtual ~SkGradientShaderBase();
 
+#if 0
     virtual bool setContext(const SkBitmap&, const SkPaint&, const SkMatrix&) SK_OVERRIDE;
     virtual uint32_t getFlags() SK_OVERRIDE { return fFlags; }
+#endif
+    virtual SkShader::Context* createContext(
+            const SkBitmap&, const SkPaint&, const SkMatrix&, void*) const SK_OVERRIDE {
+        return NULL;
+    }
+    virtual size_t contextSize() const SK_OVERRIDE { return 0; }
     virtual bool isOpaque() const SK_OVERRIDE;
 
     void getGradientTableBitmap(SkBitmap*) const;
 
     enum {
         /// Seems like enough for visual accuracy. TODO: if pos[] deserves
         /// it, use a larger cache.
         kCache16Bits    = 8,
         kCache16Count = (1 << kCache16Bits),
         kCache16Shift   = 16 - kCache16Bits,
@@ skipping 265 matching lines @@
     GrGLUniformManager::UniformHandle fColorStartUni;
     GrGLUniformManager::UniformHandle fColorMidUni;
     GrGLUniformManager::UniformHandle fColorEndUni;
 
     typedef GrGLEffect INHERITED;
 };
 
 #endif
 
 #endif