Stop discarding in frag shader when coverage is zero and stencil writes are enabled

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 381461a03b60e7c90bdc06925e924b4e4c3499d0..b6029fe4ee193befd5e1d426c0b4e01dcc80e95e 100644
--- a/src/gpu/gl/GrGLProgramDesc.cpp
+++ b/src/gpu/gl/GrGLProgramDesc.cpp
@@ -215,8 +215,7 @@ void GrGLProgramDesc::Build(const GrDrawState& drawState,
 
     // Here we deal with whether/how we handle color and coverage separately.
 
-    // Set these defaults and then possibly change our mind if there is coverage.
-    header->fDiscardIfZeroCoverage = false;
+    // Set this default and then possibly change our mind if there is coverage.
     header->fCoverageOutput = kModulate_CoverageOutput;
 
     // If we do have coverage determine whether it matters.
@@ -224,12 +223,6 @@ void GrGLProgramDesc::Build(const GrDrawState& drawState,
     if (!drawState.isCoverageDrawing() && !skipCoverage &&
         (drawState.numCoverageStages() > 0 || requiresCoverageAttrib)) {
 
-        // If we're stenciling then we want to discard samples that have zero coverage
-        if (drawState.getStencil().doesWrite()) {
-            header->fDiscardIfZeroCoverage = true;
-            separateCoverageFromColor = true;
-        }
-
         if (gpu->caps()->dualSourceBlendingSupport() &&
             !(blendOpts & (GrDrawState::kEmitCoverage_BlendOptFlag |
                            GrDrawState::kCoverageAsAlpha_BlendOptFlag))) {