Remove willReadDst from GrFragmentProcessor.

src/gpu/GrProcOptInfo.cpp

Index: src/gpu/GrProcOptInfo.cpp
diff --git a/src/gpu/GrProcOptInfo.cpp b/src/gpu/GrProcOptInfo.cpp
index 274c5305de3b17ef5c8747a5f5bc8caac0a0fed6..a350ef783dbe9fbe37c2437b394c8784c003f345 100644
--- a/src/gpu/GrProcOptInfo.cpp
+++ b/src/gpu/GrProcOptInfo.cpp
@@ -48,7 +48,6 @@ void GrProcOptInfo::internalCalc(const GrFragmentStage* stages,
     fFirstEffectStageIndex = 0;
     fInputColorIsUsed = true;
     fInputColor = fInOut.color();
-    fReadsDst = false;
     fReadsFragPosition = initWillReadFragmentPosition;
 
     for (int i = 0; i < stageCount; ++i) {
@@ -60,12 +59,8 @@ void GrProcOptInfo::internalCalc(const GrFragmentStage* stages,
             fFirstEffectStageIndex = i;
             fInputColorIsUsed = false;
             // Reset these since we don't care if previous stages read these values
-            fReadsDst = false;
             fReadsFragPosition = initWillReadFragmentPosition;
         }
-        if (processor->willReadDstColor()) {
-            fReadsDst = true;
-        }
         if (processor->willReadFragmentPosition()) {
             fReadsFragPosition = true;
         }
@@ -77,7 +72,6 @@ void GrProcOptInfo::internalCalc(const GrFragmentStage* stages,
             // zero stages that don't multiply the inputColor.
             fInOut.resetNonMulStageFound();
             // Reset these since we don't care if previous stages read these values
-            fReadsDst = false;
             fReadsFragPosition = initWillReadFragmentPosition;
         }
     }