Use static XPF for porter duff xp factories.

src/core/SkXfermode.cpp

Index: src/core/SkXfermode.cpp
diff --git a/src/core/SkXfermode.cpp b/src/core/SkXfermode.cpp
index ef44b1e747d927a2e5b22f87824e5dda44c88c76..83503659bd61098fe2140a6add8ff7c51c46085b 100644
--- a/src/core/SkXfermode.cpp
+++ b/src/core/SkXfermode.cpp
@@ -691,10 +691,17 @@ bool SkXfermode::AsFragmentProcessorOrXPFactory(SkXfermode* xfermode,
                                                 GrFragmentProcessor** fp,
                                                 GrXPFactory** xpf,
                                                 Coeff* src, Coeff* dst) {
+    Mode mode;
     if (NULL == xfermode) {
         SkAssertResult(ModeAsCoeff(kSrcOver_Mode, src, dst));
         *xpf = GrPorterDuffXPFactory::Create(*src, *dst);
         return true;
+    } else if (xfermode->asMode(&mode) && mode <= kLastCoeffMode) {
+        *xpf = GrPorterDuffXPFactory::Create(mode);
+        // TODO: This Line will be removed in follow up cl that handles blending and thus we won't
+        // have to set coeffs here.
+        SkAssertResult(ModeAsCoeff(mode, src, dst));
+        return true;
     } else if (xfermode->asCoeff(src, dst)) {
         *xpf = GrPorterDuffXPFactory::Create(*src, *dst);
         return true;