Revert of 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 7db689917e11cead29f878a744f8d26a3cd23d4b..f97f25c9c6edf36198805b04269b6496a540c173 100644
--- a/src/core/SkPMFloat.h
+++ b/src/core/SkPMFloat.h
@@ -12,6 +12,13 @@
 #include "SkColor.h"
 #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].
@@ -52,6 +59,8 @@
     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"