Refactor to put SkXfermode_opts inside SK_OPTS_NS.

src/opts/SkPMFloat_neon.h

Index: src/opts/SkPMFloat_neon.h
diff --git a/src/opts/SkPMFloat_neon.h b/src/opts/SkPMFloat_neon.h
index 8bee5b551aebb708c09b7557ae74ea6a8618f083..edbbc58b5accf869a15a83bfd938b738159f04c6 100644
--- a/src/opts/SkPMFloat_neon.h
+++ b/src/opts/SkPMFloat_neon.h
@@ -5,9 +5,7 @@
  * found in the LICENSE file.
  */
 
-namespace { // See SkPMFloat.h
-
-inline SkPMFloat::SkPMFloat(SkPMColor c) {
+SK_ALWAYS_INLINE SkPMFloat::SkPMFloat(SkPMColor c) {
     SkPMColorAssert(c);
     uint8x8_t   fix8    = (uint8x8_t)vdup_n_u32(c);
     uint16x8_t  fix8_16 = vmovl_u8(fix8);
@@ -16,7 +14,7 @@ inline SkPMFloat::SkPMFloat(SkPMColor c) {
     SkASSERT(this->isValid());
 }
 
-inline SkPMColor SkPMFloat::round() const {
+SK_ALWAYS_INLINE SkPMColor SkPMFloat::round() const {
     // vcvt_u32_f32 truncates, so we round manually by adding a half before converting.
     float32x4_t rounded = vmlaq_f32(vdupq_n_f32(0.5f), fVec, vdupq_n_f32(255));
     uint32x4_t  fix8_32 = vcvtq_u32_f32(rounded);
@@ -27,9 +25,7 @@ inline SkPMColor SkPMFloat::round() const {
     return c;
 }
 
-inline Sk4f SkPMFloat::alphas() const {
+SK_ALWAYS_INLINE Sk4f SkPMFloat::alphas() const {
     static_assert(SK_A32_SHIFT == 24, "Assuming little-endian.");
     return vdupq_lane_f32(vget_high_f32(fVec), 1);  // Duplicate high lane of high half i.e. lane 3.
 }
-
-}  // namespace