Disable blending when there is an effect that reads the dst and draw state blend is 1,0.

src/gpu/GrDrawState.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrDrawState.h"
 #include "GrPaint.h"
 
@@ skipping 353 matching lines @@
                 *dstCoeff = kISA_GrBlendCoeff;
                 return  kCoverageAsAlpha_BlendOptFlag;
             }
         } else if (dstCoeffIsOne) {
             // the dst coeff is effectively one so blend works out to:
             // cS + (c)(1)D + (1-c)D = cS + D.
             *dstCoeff = kOne_GrBlendCoeff;
             return  kCoverageAsAlpha_BlendOptFlag;
         }
     }
+    if (kOne_GrBlendCoeff == *srcCoeff &&
+        kZero_GrBlendCoeff == *dstCoeff &&
+        this->willEffectReadDstColor()) {
+        // In this case the shader will fully resolve the color, coverage, and dst and we don't
+        // need blending.
+        return kDisableBlend_BlendOptFlag;
+    }
     return kNone_BlendOpt;
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 void GrDrawState::AutoViewMatrixRestore::restore() {
     if (NULL != fDrawState) {
         fDrawState->setViewMatrix(fViewMatrix);
         for (int s = 0; s < GrDrawState::kNumStages; ++s) {
             if (fRestoreMask & (1 << s)) {
@@ skipping 65 matching lines @@
             }
             fRestoreMask |= (1 << s);
             GrEffectStage* stage = drawState->fStages + s;
             stage->saveCoordChange(&fSavedCoordChanges[s]);
             stage->localCoordChange(invVM);
         }
     }
     drawState->viewMatrix()->reset();
     return true;
 }