Remove canTweakAlphaForCoverage from XP's since batch reads flag.

src/gpu/GrPipelineBuilder.cpp

Index: src/gpu/GrPipelineBuilder.cpp
diff --git a/src/gpu/GrPipelineBuilder.cpp b/src/gpu/GrPipelineBuilder.cpp
index 98deee9bb82ab146657f16520d6a120aec6dc9b6..3b722e2b1d169e134dff985a269d708db021961a 100644
--- a/src/gpu/GrPipelineBuilder.cpp
+++ b/src/gpu/GrPipelineBuilder.cpp
@@ -117,14 +117,6 @@ void GrPipelineBuilder::AutoRestoreFragmentProcessors::set(GrPipelineBuilder* pi
 
 ////////////////////////////////////////////////////////////////////////////////
 
-// Some blend modes allow folding a fractional coverage value into the color's alpha channel, while
-// others will blend incorrectly.
-bool GrPipelineBuilder::canTweakAlphaForCoverage() const {
-    return this->getXPFactory()->canTweakAlphaForCoverage();
-}
-
-////////////////////////////////////////////////////////////////////////////////
-
 GrPipelineBuilder::~GrPipelineBuilder() {
     SkASSERT(0 == fBlockEffectRemovalCnt);
 }