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

The primary feature this delivers is SkNf and SkNd for arbitrary power-of-two N.  Non-specialized types or types larger than 128 bits should now Just Work (and we can drop in a specialization to make them faster).  Sk4s is now just a typedef for SkNf<4, SkScalar>; Sk4d is SkNf<4, double>, Sk2f SkNf<2, float>, etc.

This also makes implementing new specializations easier and more encapsulated.  We're now using template specialization, which means the specialized versions don't have to leak out so much from SkNx_sse.h  and SkNx_neon.h.

This design leaves us room to grow up, e.g to SkNf<8, SkScalar> == Sk8s, and to grown down too, to things like SkNi<8, uint16_t> == Sk8h.

To simplify things, I've stripped away most APIs (swizzles, casts, reinterpret_casts) that no one's using yet.  I will happily add them back if they seem useful.

You shouldn't feel bad about using any of the typedef Sk4s, Sk4f, Sk4d, Sk2s, Sk2f, Sk2d, Sk4i, etc.  Here's how you should feel:
  - Sk4f, Sk4s, Sk2d: feel awesome
  - Sk2f, Sk2s, Sk4d: feel pretty good

No public API changes.
TBR=reed@google.com

BUG=skia:3592

Review URL: https://codereview.chromium.org/1048593002

1 files changed, 3 insertions, 8 deletions

diff --git a/src/opts/SkPMFloat_neon.h b/src/opts/SkPMFloat_neon.h
index e5b16f5e6f..41c553ebb9 100644
--- a/src/opts/SkPMFloat_neon.h
+++ b/src/opts/SkPMFloat_neon.h
@@ -5,11 +5,6 @@
  * found in the LICENSE file.
  */
 
-inline SkPMFloat& SkPMFloat::operator=(const SkPMFloat& that) {
-    fColors = that.fColors;
-    return *this;
-}
-
 // For SkPMFloat(SkPMFColor), we widen our 8 bit components (fix8) to 8-bit components in 16 bits
 // (fix8_16), then widen those to 8-bit-in-32-bits (fix8_32), and finally convert those to floats.
 
@@ -27,7 +22,7 @@ inline SkPMFloat::SkPMFloat(SkPMColor c) {
 }
 
 inline SkPMColor SkPMFloat::trunc() const {
-    uint32x4_t  fix8_32  = vcvtq_u32_f32(fColors);  // vcvtq_u32_f32 truncates
+    uint32x4_t  fix8_32  = vcvtq_u32_f32(fColors.vec());  // vcvtq_u32_f32 truncates
     uint16x4_t  fix8_16  = vmovn_u32(fix8_32);
     uint8x8_t   fix8     = vmovn_u16(vcombine_u16(fix8_16, vdup_n_u16(0)));
     SkPMColor c = vget_lane_u32((uint32x2_t)fix8, 0);
@@ -37,11 +32,11 @@ inline SkPMColor SkPMFloat::trunc() const {
 
 inline SkPMColor SkPMFloat::get() const {
     SkASSERT(this->isValid());
-    return SkPMFloat(Sk4f(0.5f) + *this).trunc();
+    return SkPMFloat(Sk4s(0.5f) + *this).trunc();
 }
 
 inline SkPMColor SkPMFloat::clamped() const {
-    float32x4_t add_half = vaddq_f32(fColors, vdupq_n_f32(0.5f));
+    float32x4_t add_half = vaddq_f32(fColors.vec(), vdupq_n_f32(0.5f));
     uint32x4_t  fix8_32  = vcvtq_u32_f32(add_half);  // vcvtq_u32_f32 truncates, so round manually
     uint16x4_t  fix8_16  = vqmovn_u32(fix8_32);
     uint8x8_t   fix8     = vqmovn_u16(vcombine_u16(fix8_16, vdup_n_u16(0)));