Refactor to put SkXfermode_opts inside SK_OPTS_NS.

src/core/SkPMFloat.h

Index: src/core/SkPMFloat.h
diff --git a/src/core/SkPMFloat.h b/src/core/SkPMFloat.h
index f97f25c9c6edf36198805b04269b6496a540c173..7db689917e11cead29f878a744f8d26a3cd23d4b 100644
--- a/src/core/SkPMFloat.h
+++ b/src/core/SkPMFloat.h
@@ -13,13 +13,6 @@
 #include "SkColorPriv.h"
 #include "SkNx.h"
 
-// This file may be included multiple times by .cpp files with different flags, leading
-// to different definitions.  Usually that doesn't matter because it's all inlined, but
-// in Debug modes the compilers may not inline everything.  So wrap everything in an
-// anonymous namespace to give each includer their own silo of this code (or the linker
-// will probably pick one randomly for us, which is rarely correct).
-namespace {
-
 // A pre-multiplied color storing each component in the same order as SkPMColor,
 // but as a float in the range [0, 1].
 class SkPMFloat : public Sk4f {
@@ -59,8 +52,6 @@ private:
     typedef Sk4f INHERITED;
 };
 
-}  // namespace
-
 #ifdef SKNX_NO_SIMD
     // Platform implementations of SkPMFloat assume Sk4f uses SSE or NEON.  _none is generic.
     #include "../opts/SkPMFloat_none.h"