Added function CreateFrom2Procs() in new namespace GrXfermodeFragmentProcessor

include/gpu/effects/GrXfermodeFragmentProcessor.h

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrXfermodeFragmentProcessor_DEFINED
+#define GrXfermodeFragmentProcessor_DEFINED
+
+#include "SkXfermode.h"
+
+class GrFragmentProcessor;
+
+namespace GrXfermodeFragmentProcessor {
+    const GrFragmentProcessor* CreateFrom2Procs(const GrFragmentProcessor* src,

[bsalomon, 2015/09/08 15:10:57]

Not crazy about "Procs". AFAIK it isn't a standard term we use in other code
that deals with fragment processors. I'd like to restrict adding new terminology
to cases that aren't duplicated with other terms and add value.

Ok with avoiding the full "FragmentProcessors" to keep the name shorter.
CreateBlendBetweenTwo? CreateComposeTwo?

+                                                const GrFragmentProcessor* dst,
+                                                SkXfermode::Mode mode);
+};
+
+#endif