Remove GP from drawstate, revision of invariant output for GP

include/gpu/GrXferProcessor.h

Index: include/gpu/GrXferProcessor.h
diff --git a/include/gpu/GrXferProcessor.h b/include/gpu/GrXferProcessor.h
index b7d0bdd9fa9ef7717471a3857b9e788e95793378..39dc2120882f7c3d1e31a1519180580fe68ac69c 100644
--- a/include/gpu/GrXferProcessor.h
+++ b/include/gpu/GrXferProcessor.h
@@ -87,6 +87,16 @@ public:
     /** Will this prceossor read the destination pixel value? */
     bool willReadDstColor() const { return fWillReadDstColor; }
 
+    /**
+     * This function is used to perform optimizations. When called the invarientOuput param
+     * indicate whether the input components to this processor in the FS will have known values.
+     * In inout the validFlags member is a bitfield of GrColorComponentFlags. The isSingleComponent
+     * member indicates whether the input will be 1 or 4 bytes. The function updates the members of
+     * inout to indicate known values of its output. A component of the color member only has
+     * meaning if the corresponding bit in validFlags is set.
+     */
+    void computeInvariantOutput(GrInvariantOutput* inout) const;
+
 protected:
     GrXferProcessor() : fWillReadDstColor(false) {}
 
@@ -97,6 +107,11 @@ protected:
      */
     void setWillReadDstColor() { fWillReadDstColor = true; }
 
+    /**
+     * Subclass implements this to support getConstantColorComponents(...).
+     */
+    virtual void onComputeInvariantOutput(GrInvariantOutput* inout) const = 0;
+
 private:
 
     bool         fWillReadDstColor;