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

src/gpu/GrDrawState.cpp

Index: src/gpu/GrDrawState.cpp
diff --git a/src/gpu/GrDrawState.cpp b/src/gpu/GrDrawState.cpp
index 591e157129af4aa7846cda18bf949ec4f8e04861..a3850b087e7abcabbdcc45ce65c07124a29bc3c2 100644
--- a/src/gpu/GrDrawState.cpp
+++ b/src/gpu/GrDrawState.cpp
@@ -371,6 +371,13 @@ GrDrawState::BlendOptFlags GrDrawState::getBlendOpts(bool forceCoverage,
             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;
 }