Work in progress to make SkShader immutable.

include/core/SkComposeShader.h

Index: include/core/SkComposeShader.h
diff --git a/include/core/SkComposeShader.h b/include/core/SkComposeShader.h
index 1fefd1369a1c3eec87146f43abeacd02b9aa0c54..bf6fce7545a9bb7a60cf20afe52e6c0e3c1820b7 100644
--- a/include/core/SkComposeShader.h
+++ b/include/core/SkComposeShader.h
@@ -34,10 +34,10 @@ public:
     SkComposeShader(SkShader* sA, SkShader* sB, SkXfermode* mode = NULL);
     virtual ~SkComposeShader();
 
-    virtual bool setContext(const SkBitmap&, const SkPaint&,
-                            const SkMatrix&) SK_OVERRIDE;
-    virtual void endContext() SK_OVERRIDE;
-    virtual void shadeSpan(int x, int y, SkPMColor[], int count) SK_OVERRIDE;
+    virtual bool onSetContext(Context* c, const SkBitmap&, const SkPaint&,
+                              const SkMatrix&) SK_OVERRIDE;
+    virtual void endContext(Context* c) SK_OVERRIDE;
+    virtual void shadeSpan(Context* c, int x, int y, SkPMColor[], int count) SK_OVERRIDE;
 
     SK_DEVELOPER_TO_STRING()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkComposeShader)
@@ -47,11 +47,14 @@ protected:
     virtual void flatten(SkWriteBuffer&) const SK_OVERRIDE;
 
 private:
-
     SkShader*   fShaderA;
     SkShader*   fShaderB;
     SkXfermode* fMode;
 
+    DEFINE_CONTEXT_RETRIEVAL_FUNCTIONS()
+
+    size_t getMySpaceNeededForContext() const;
+
     typedef SkShader INHERITED;
 };