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

src/core/SkBlitter.h

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkBlitter_DEFINED
@@ skipping 43 matching lines @@
     */
     virtual const SkBitmap* justAnOpaqueColor(uint32_t* value);
 
     /**
      *  Special method just to identify the null blitter, which is returned
      *  from Choose() if the request cannot be fulfilled. Default impl
      *  returns false.
      */
     virtual bool isNullBlitter() const;
 
+    /**
+     *  Special method for SkShaderBlitter. On all other classes this is a no-op.
+     */
+    virtual bool resetShaderContext(const SkBitmap& device, const SkPaint& paint,
+                                    const SkMatrix& matrix);
+
     ///@name non-virtual helpers
     void blitMaskRegion(const SkMask& mask, const SkRegion& clip);
     void blitRectRegion(const SkIRect& rect, const SkRegion& clip);
     void blitRegion(const SkRegion& clip);
     ///@}
 
     /** @name Factories
         Return the correct blitter to use given the specified context.
      */
     static SkBlitter* Choose(const SkBitmap& device,
@@ skipping 89 matching lines @@
     SkBlitter*  apply(SkBlitter* blitter, const SkRegion* clip,
                       const SkIRect* bounds = NULL);
 
 private:
     SkNullBlitter       fNullBlitter;
     SkRectClipBlitter   fRectBlitter;
     SkRgnClipBlitter    fRgnBlitter;
 };
 
 #endif