Replace fWillReadFragmentPosition with a bitfield

src/gpu/GrPipeline.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrPipeline_DEFINED
 #define GrPipeline_DEFINED
 
@@ skipping 142 matching lines @@
     /**
      * Gets whether the target is drawing clockwise, counterclockwise,
      * or both faces.
      * @return the current draw face(s).
      */
     GrPipelineBuilder::DrawFace getDrawFace() const { return fDrawFace; }
 
 
     ///////////////////////////////////////////////////////////////////////////
 
-    bool readsFragPosition() const { return fReadsFragPosition; }
+    bool readsFragPosition() const {
+        return fBuiltInState & GrProcessor::kFragmentPosition_BuiltInState;
+    }
+
     bool ignoresCoverage() const { return fIgnoresCoverage; }
 
 private:
     GrPipeline() { /** Initialized in factory function*/ }
 
     /**
      * Alter the program desc and inputs (attribs and processors) based on the blend optimization.
      */
     void adjustProgramFromOptimizations(const GrPipelineBuilder& ds,
                                         GrXferProcessor::OptFlags,
@@ skipping 19 matching lines @@
     typedef GrPendingProgramElement<const GrFragmentProcessor> PendingFragmentProcessor;
     typedef SkAutoSTArray<8, PendingFragmentProcessor> FragmentProcessorArray;
     typedef GrPendingProgramElement<const GrXferProcessor> ProgramXferProcessor;
     RenderTarget                        fRenderTarget;
     GrScissorState                      fScissorState;
     GrStencilSettings                   fStencilSettings;
     GrPipelineBuilder::DrawFace         fDrawFace;
     uint32_t                            fFlags;
     ProgramXferProcessor                fXferProcessor;
     FragmentProcessorArray              fFragmentProcessors;
-    bool                                fReadsFragPosition;
+    GrProcessor::BuiltInState           fBuiltInState;
     bool                                fIgnoresCoverage;
 
     // This value is also the index in fFragmentProcessors where coverage processors begin.
     int                                 fNumColorProcessors;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif