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

include/effects/SkTransparentShader.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 SkTransparentShader_DEFINED
 #define SkTransparentShader_DEFINED
 
 #include "SkShader.h"
 
 class SK_API SkTransparentShader : public SkShader {
 public:
     SkTransparentShader() {}
 
-    virtual SkShader::Context* createContext(const SkBitmap& device, const SkPaint& paint,
-                                             const SkMatrix& matrix, void* storage) const
-            SK_OVERRIDE;
-    virtual size_t contextSize() const SK_OVERRIDE;
-
-    class TransparentShaderContext : public SkShader::Context {
-    public:
-        TransparentShaderContext(const SkTransparentShader& shader, const SkBitmap& device,
-                                 const SkPaint& paint, const SkMatrix& matrix);
-        virtual ~TransparentShaderContext();
-
-        virtual uint32_t getFlags() const SK_OVERRIDE;
-        virtual void shadeSpan(int x, int y, SkPMColor[], int count) SK_OVERRIDE;
-        virtual void shadeSpan16(int x, int y, uint16_t span[], int count) SK_OVERRIDE;
-
-    private:
-        const SkBitmap* fDevice;
-
-        typedef SkShader::Context INHERITED;
-    };
+    virtual uint32_t getFlags() SK_OVERRIDE;
+    virtual bool    setContext(const SkBitmap& device,
+                               const SkPaint& paint,
+                               const SkMatrix& matrix) SK_OVERRIDE;
+    virtual void    shadeSpan(int x, int y, SkPMColor[], int count) SK_OVERRIDE;
+    virtual void    shadeSpan16(int x, int y, uint16_t span[], int count) SK_OVERRIDE;
 
     SK_TO_STRING_OVERRIDE()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkTransparentShader)
 
 private:
+    // these are a cache from the call to setContext()
+    const SkBitmap* fDevice;
+    uint8_t         fAlpha;
+
     SkTransparentShader(SkReadBuffer& buffer) : INHERITED(buffer) {}
 
     typedef SkShader INHERITED;
 };
 
 #endif