Refactor Sk2x<T> + Sk4x<T> into SkNf<N,T> and SkNi<N,T>

src/core/SkPMFloat.h

Index: src/core/SkPMFloat.h
diff --git a/src/core/SkPMFloat.h b/src/core/SkPMFloat.h
index 66262a8916ae772ef59d78db76d4aae0c840d095..27f6f78f26028e47fca9f24ff2908f90faf40f60 100644
--- a/src/core/SkPMFloat.h
+++ b/src/core/SkPMFloat.h
@@ -11,13 +11,7 @@
 #include "SkTypes.h"
 #include "SkColor.h"
 #include "SkColorPriv.h"
-#include "Sk4x.h"
-
-#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
-    #include <immintrin.h>
-#elif defined(SK_ARM_HAS_NEON)
-    #include <arm_neon.h>
-#endif
+#include "SkNx.h"
 
 // A pre-multiplied color storing each component in the same order as SkPMColor,
 // but as a float in the range [0, 255].
@@ -29,29 +23,25 @@ public:
     // May be more efficient than one at a time.  No special alignment assumed for SkPMColors.
     static void From4PMColors(const SkPMColor[4], SkPMFloat*, SkPMFloat*, SkPMFloat*, SkPMFloat*);
 
-    explicit SkPMFloat(SkPMColor);
-    SkPMFloat(float a, float r, float g, float b) {
-        // TODO: faster when specialized?
-        fColor[SK_A32_SHIFT / 8] = a;
-        fColor[SK_R32_SHIFT / 8] = r;
-        fColor[SK_G32_SHIFT / 8] = g;
-        fColor[SK_B32_SHIFT / 8] = b;
-    }
-
     // Uninitialized.
     SkPMFloat() {}
+    explicit SkPMFloat(SkPMColor);
+    SkPMFloat(float a, float r, float g, float b)
+    #ifdef SK_PMCOLOR_IS_RGBA
+        : fColors(r,g,b,a) {}
+    #else
+        : fColors(b,g,r,a) {}
+    #endif
 
-    SkPMFloat(const SkPMFloat& that) { *this = that; }
-    SkPMFloat& operator=(const SkPMFloat& that);
 
-    // Freely autoconvert between SkPMFloat and Sk4f.  They're always byte-for-byte identical.
-    /*implicit*/ SkPMFloat(const Sk4f& fs) { fs.storeAligned(fColor); }
-    /*implicit*/ operator Sk4f() const { return Sk4f::LoadAligned(fColor); }
+    // Freely autoconvert between SkPMFloat and Sk4s.
+    /*implicit*/ SkPMFloat(const Sk4s& fs) { fColors = fs; }
+    /*implicit*/ operator Sk4s() const { return fColors; }
 
-    float a() const { return fColor[SK_A32_SHIFT / 8]; }
-    float r() const { return fColor[SK_R32_SHIFT / 8]; }
-    float g() const { return fColor[SK_G32_SHIFT / 8]; }
-    float b() const { return fColor[SK_B32_SHIFT / 8]; }
+    float a() const { return fColors[SK_A32_SHIFT / 8]; }
+    float r() const { return fColors[SK_R32_SHIFT / 8]; }
+    float g() const { return fColors[SK_G32_SHIFT / 8]; }
+    float b() const { return fColors[SK_B32_SHIFT / 8]; }
 
     // get() and clamped() round component values to the nearest integer.
     SkPMColor     get() const;  // May SkASSERT(this->isValid()).  Some implementations may clamp.
@@ -75,24 +65,22 @@ public:
     }
 
 private:
-    union {
-        float fColor[4];
-#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
-        __m128 fColors;
-#elif defined(SK_ARM_HAS_NEON)
-        float32x4_t fColors;
-#endif
-    };
+    Sk4s fColors;
 };
 
-#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSSE3
-    #include "../opts/SkPMFloat_SSSE3.h"
-#elif SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
-    #include "../opts/SkPMFloat_SSE2.h"
-#elif defined(SK_ARM_HAS_NEON)
-    #include "../opts/SkPMFloat_neon.h"
-#else
+#ifdef SKNX_NO_SIMD
+    // Platform implementations of SkPMFloat assume Sk4s uses SSE or NEON.  _none is generic.
     #include "../opts/SkPMFloat_none.h"
+#else
+    #if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSSE3
+        #include "../opts/SkPMFloat_SSSE3.h"
+    #elif SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
+        #include "../opts/SkPMFloat_SSE2.h"
+    #elif defined(SK_ARM_HAS_NEON)
+        #include "../opts/SkPMFloat_neon.h"
+    #else
+        #include "../opts/SkPMFloat_none.h"
+    #endif
 #endif
 
 #endif//SkPM_DEFINED