Revert of Code's more readable when SkPMFloat is an Sk4f.

src/opts/SkNx_sse.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 SkNx_sse_DEFINED
 #define SkNx_sse_DEFINED
 
@@ skipping 128 matching lines @@
 
 private:
     __m128d fVec;
 };
 
 template <>
 class SkNf<4, float> {
     typedef SkNi<4, int32_t> Ni;
 public:
     SkNf(const __m128& vec) : fVec(vec) {}
+    __m128 vec() const { return fVec; }
 
     SkNf() {}
     explicit SkNf(float val)           : fVec( _mm_set1_ps(val) ) {}
     static SkNf Load(const float vals[4]) { return _mm_loadu_ps(vals); }
     SkNf(float a, float b, float c, float d) : fVec(_mm_setr_ps(a,b,c,d)) {}
 
     void store(float vals[4]) const { _mm_storeu_ps(vals, fVec); }
 
     SkNf operator + (const SkNf& o) const { return _mm_add_ps(fVec, o.fVec); }
     SkNf operator - (const SkNf& o) const { return _mm_sub_ps(fVec, o.fVec); }
@@ skipping 15 matching lines @@
 
     SkNf       invert() const { return SkNf(1) / *this; }
     SkNf approxInvert() const { return _mm_rcp_ps(fVec); }
 
     template <int k> float kth() const {
         SkASSERT(0 <= k && k < 4);
         union { __m128 v; float fs[4]; } pun = {fVec};
         return pun.fs[k&3];
     }
 
-protected:
+private:
     __m128 fVec;
 };
 
 
 #endif//SkNx_sse_DEFINED