Re-enable advanced blend with a blacklist

src/gpu/effects/GrCustomXfermode.cpp

Index: src/gpu/effects/GrCustomXfermode.cpp
diff --git a/src/gpu/effects/GrCustomXfermode.cpp b/src/gpu/effects/GrCustomXfermode.cpp
index b43d2d4ce64516d27a5e0d970b00658935e10dbb..794e55efdcf9bd99e68723bfa7440fb110db1641 100644
--- a/src/gpu/effects/GrCustomXfermode.cpp
+++ b/src/gpu/effects/GrCustomXfermode.cpp
@@ -51,13 +51,18 @@ static GrBlendEquation hw_blend_equation(SkXfermode::Mode mode) {
     GR_STATIC_ASSERT(kGrBlendEquationCnt == SkXfermode::kLastMode + 1 + kOffset);
 }
 
-static bool can_use_hw_blend_equation(const GrProcOptInfo& coveragePOI, const GrCaps& caps) {
+static bool can_use_hw_blend_equation(GrBlendEquation equation,
+                                      const GrProcOptInfo& coveragePOI,
+                                      const GrCaps& caps) {
     if (!caps.advancedBlendEquationSupport()) {
         return false;
     }
     if (coveragePOI.isFourChannelOutput()) {
         return false; // LCD coverage must be applied after the blend equation.
     }
+    if (caps.canUseAdvancedBlendEquation(equation)) {
+        return false;
+    }
     return true;
 }
 
@@ -788,7 +793,7 @@ GrCustomXPFactory::onCreateXferProcessor(const GrCaps& caps,
                                          const GrProcOptInfo& coveragePOI,
                                          bool hasMixedSamples,
                                          const DstTexture* dstTexture) const {
-    if (can_use_hw_blend_equation(coveragePOI, caps)) {
+    if (can_use_hw_blend_equation(fHWBlendEquation, coveragePOI, caps)) {
         SkASSERT(!dstTexture || !dstTexture->texture());
         return SkNEW_ARGS(CustomXP, (fMode, fHWBlendEquation));
     }
@@ -799,7 +804,7 @@ bool GrCustomXPFactory::willReadDstColor(const GrCaps& caps,
                                          const GrProcOptInfo& colorPOI,
                                          const GrProcOptInfo& coveragePOI,
                                          bool hasMixedSamples) const {
-    return !can_use_hw_blend_equation(coveragePOI, caps);
+    return !can_use_hw_blend_equation(fHWBlendEquation, coveragePOI, caps);
 }
 
 void GrCustomXPFactory::getInvariantBlendedColor(const GrProcOptInfo& colorPOI,