Remove willReadDst from GrFragmentProcessor.

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
 
@@ skipping 10 matching lines @@
  * 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)
         , fFirstEffectStageIndex(0)
         , fInputColorIsUsed(true)
         , fInputColor(0)
-        , fReadsDst(false)
         , fReadsFragPosition(false) {}
 
     void calcWithInitialValues(const GrFragmentStage*, int stageCount, GrColor startColor,
                                GrColorComponentFlags flags, bool areCoverageStages);
 
     void calcColorWithPrimProc(const GrPrimitiveProcessor*, const GrFragmentStage*, int stagecount);
     void calcCoverageWithPrimProc(const GrPrimitiveProcessor*, const GrFragmentStage*,
                                   int stagecount);
 
     bool isSolidWhite() const { return fInOut.isSolidWhite(); }
@@ skipping 26 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 stage.
      */
     GrColor inputColorToEffectiveStage() const { return fInputColor; }
 
     /**
-     * Returns true if any of the stages preserved by GrProcOptInfo read the dst color.
-     */
-    bool readsDst() const { return fReadsDst; }
-
-    /**
      * Returns true if any of the stages preserved by GrProcOptInfo read the frag position.
      */
     bool readsFragPosition() const { return fReadsFragPosition; }
 
 private:
     void internalCalc(const GrFragmentStage*, int stagecount, bool initWillReadFragPosition);
 
     GrInvariantOutput fInOut;
     int fFirstEffectStageIndex;
     bool fInputColorIsUsed;
     GrColor fInputColor;
-    bool fReadsDst;
     bool fReadsFragPosition;
 };
 
 #endif