create struct to hold all the params passed around for shader::context

src/core/SkPictureShader.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkPictureShader_DEFINED
 #define SkPictureShader_DEFINED
 
 #include "SkShader.h"
 
 class SkBitmap;
 class SkPicture;
 
 /*
  * An SkPictureShader can be used to draw SkPicture-based patterns.
  *
  * The SkPicture is first rendered into a tile, which is then used to shade the area according
  * to specified tiling rules.
  */
 class SkPictureShader : public SkShader {
 public:
     static SkPictureShader* Create(SkPicture*, TileMode, TileMode);
     virtual ~SkPictureShader();
 
-    virtual bool validContext(const SkBitmap&, const SkPaint&,
-                              const SkMatrix&, SkMatrix* totalInverse = NULL) const SK_OVERRIDE;
-    virtual SkShader::Context* createContext(const SkBitmap& device, const SkPaint& paint,
-                                             const SkMatrix& matrix, void* storage) const
-            SK_OVERRIDE;
+    virtual bool validContext(const ContextRec&, SkMatrix* totalInverse) const SK_OVERRIDE;
+    virtual SkShader::Context* createContext(const ContextRec&, void* storage) const SK_OVERRIDE;
     virtual size_t contextSize() const SK_OVERRIDE;
 
     class PictureShaderContext : public SkShader::Context {
     public:
-        PictureShaderContext(const SkPictureShader& shader, const SkBitmap& device,
-                             const SkPaint& paint, const SkMatrix& matrix,
-                             SkShader* bitmapShader);
+        PictureShaderContext(const SkPictureShader&, const ContextRec&, SkShader* bitmapShader);
         virtual ~PictureShaderContext();
 
         virtual uint32_t getFlags() const SK_OVERRIDE;
 
         virtual ShadeProc asAShadeProc(void** ctx) SK_OVERRIDE;
         virtual void shadeSpan(int x, int y, SkPMColor dstC[], int count) SK_OVERRIDE;
         virtual void shadeSpan16(int x, int y, uint16_t dstC[], int count) SK_OVERRIDE;
 
     private:
         SkAutoTUnref<SkShader>  fBitmapShader;
@@ skipping 10 matching lines @@
     GrEffectRef* asNewEffect(GrContext*, const SkPaint&) const SK_OVERRIDE;
 #endif
 
 protected:
     SkPictureShader(SkReadBuffer&);
     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
 
 private:
     SkPictureShader(SkPicture*, TileMode, TileMode);
 
-    SkShader* validInternal(const SkBitmap& device, const SkPaint& paint,
-                            const SkMatrix& matrix, SkMatrix* totalInverse) const;
-
+    SkShader* validInternal(const ContextRec&, SkMatrix* totalInverse) const;
     SkShader* refBitmapShader(const SkMatrix&) const;
 
     SkPicture*  fPicture;
     TileMode    fTmx, fTmy;
 
     mutable SkMutex                 fCachedBitmapShaderMutex;
     mutable SkAutoTUnref<SkShader>  fCachedBitmapShader;
     mutable SkSize                  fCachedTileScale;
     mutable SkMatrix                fCachedLocalMatrix;
 
     typedef SkShader INHERITED;
 };
 
 #endif // SkPictureShader_DEFINED