Replace fWillReadFragmentPosition with a bitfield

src/gpu/GrProcOptInfo.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 GrProcOptInfo_DEFINED
 #define GrProcOptInfo_DEFINED
 
 #include "GrColor.h"
 #include "GrInvariantOutput.h"
+#include "GrProcessor.h"
 
 class GrDrawBatch;
 class GrFragmentProcessor;
 class GrPrimitiveProcessor;
-class GrProcessor;
 
 /**
  * GrProcOptInfo gathers invariant data from a set of processor stages.It is used to recognize
  * optimizations related to eliminating stages and vertex attributes that aren't necessary for a
  * draw.
  */
 class GrProcOptInfo {
 public:
     GrProcOptInfo()
         : fInOut(0, static_cast<GrColorComponentFlags>(0), false)
         , fFirstEffectiveProcessorIndex(0)
         , fInputColorIsUsed(true)
         , fInputColor(0)
-        , fReadsFragPosition(false) {}
+        , fBuiltInState(GrProcessor::kNone_BuiltInState) {}
 
     void calcWithInitialValues(const GrFragmentProcessor* const *, int cnt, GrColor startColor,
                                GrColorComponentFlags, bool areCoverageStages, bool isLCD = false);
     void initUsingInvariantOutput(GrInitInvariantOutput invOutput);
     void completeCalculations(const GrFragmentProcessor * const processors[], int cnt);
     
     bool isSolidWhite() const { return fInOut.isSolidWhite(); }
     bool isOpaque() const { return fInOut.isOpaque(); }
     bool isSingleComponent() const { return fInOut.isSingleComponent(); }
     bool allStagesMultiplyInput() const { return fInOut.allStagesMulInput(); }
@@ skipping 27 matching lines @@
      */
     bool inputColorIsUsed() const { return fInputColorIsUsed; }
 
     /**
      * If input color is used and per-vertex colors are not used, this is the input color to the
      * first effective processor.
      */
     GrColor inputColorToFirstEffectiveProccesor() const { return fInputColor; }
 
     /**
-     * Returns true if any of the processor preserved by GrProcOptInfo read the frag position.
+     * Returns the set of built-in state used by the processors preserved by GrProcOptInfo.
      */
-    bool readsFragPosition() const { return fReadsFragPosition; }
+    GrProcessor::BuiltInState builtInState() const { return fBuiltInState; }
 
 private:
-    void internalCalc(const GrFragmentProcessor* const[], int cnt, bool initWillReadFragPosition);
+    void internalCalc(const GrFragmentProcessor* const[], int cnt);
 
     GrInvariantOutput fInOut;
     int fFirstEffectiveProcessorIndex;
     bool fInputColorIsUsed;
     GrColor fInputColor;
-    bool fReadsFragPosition;
+    GrProcessor::BuiltInState fBuiltInState;
 };
 
 #endif