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

src/gpu/gl/GrGLProgramDesc.cpp

Index: src/gpu/gl/GrGLProgramDesc.cpp
diff --git a/src/gpu/gl/GrGLProgramDesc.cpp b/src/gpu/gl/GrGLProgramDesc.cpp
index 532923a19c0d4c3e6907bf761441423896abaffd..e8812fade79d743cb30146ec858ff7d1b01a18fc 100644
--- a/src/gpu/gl/GrGLProgramDesc.cpp
+++ b/src/gpu/gl/GrGLProgramDesc.cpp
@@ -178,8 +178,8 @@ void GrGLProgramDesc::Build(const GrDrawState& drawState,
                 desc->fFirstCoverageStage = firstCoverageStage;
             }
         } else if (readsDst &&
-                   kOne_GrBlendCoeff == drawState.getSrcBlendCoeff() &&
-                   kZero_GrBlendCoeff == drawState.getDstBlendCoeff()) {
+                   kOne_GrBlendCoeff == srcCoeff &&
+                   kZero_GrBlendCoeff == dstCoeff) {
             desc->fCoverageOutput = kCombineWithDst_CoverageOutput;
             desc->fFirstCoverageStage = firstCoverageStage;
         }