Templatize SkPMFloat to support both 1 and 255 biases.

src/opts/SkXfermode_opts.h

Index: src/opts/SkXfermode_opts.h
diff --git a/src/opts/SkXfermode_opts.h b/src/opts/SkXfermode_opts.h
index 7005d593afe698c724336e1bbe58a0d317295f2c..bb92af9bb615f101ed66600c1137b84f229c3205 100644
--- a/src/opts/SkXfermode_opts.h
+++ b/src/opts/SkXfermode_opts.h
@@ -110,7 +110,7 @@ XFERMODE(Lighten) {
 #undef XFERMODE
 
 // Some xfermodes use math like divide or sqrt that's best done in floats 1 pixel at a time.
-#define XFERMODE(Name) static SkPMFloat SK_VECTORCALL Name(SkPMFloat d, SkPMFloat s)
+#define XFERMODE(Name) static SkPMFloat<1> SK_VECTORCALL Name(SkPMFloat<1> d, SkPMFloat<1> s)
 
 XFERMODE(ColorDodge) {
     auto sa = s.alphas(),
@@ -126,7 +126,7 @@ XFERMODE(ColorDodge) {
     auto colors = (d == Sk4f(0)).thenElse(dstover,
                   (s ==      sa).thenElse(srcover,
                                           otherwise));
-    return srcover * SkPMFloat(1,0,0,0) + colors * SkPMFloat(0,1,1,1);
+    return srcover * SkPMFloat<1>(1,0,0,0) + colors * SkPMFloat<1>(0,1,1,1);
 }
 XFERMODE(ColorBurn) {
     auto sa = s.alphas(),
@@ -142,7 +142,7 @@ XFERMODE(ColorBurn) {
     auto colors = (d ==      da).thenElse(dstover,
                   (s == Sk4f(0)).thenElse(srcover,
                                           otherwise));
-    return srcover * SkPMFloat(1,0,0,0) + colors * SkPMFloat(0,1,1,1);
+    return srcover * SkPMFloat<1>(1,0,0,0) + colors * SkPMFloat<1>(0,1,1,1);
 }
 XFERMODE(SoftLight) {
     auto sa = s.alphas(),
@@ -167,7 +167,7 @@ XFERMODE(SoftLight) {
     auto alpha  = s + d*isa;
     auto colors = s*ida + d*isa + (s2 <= sa).thenElse(darkSrc, liteSrc);           // Case 1 or 2/3?
 
-    return alpha * SkPMFloat(1,0,0,0) + colors * SkPMFloat(0,1,1,1);
+    return alpha * SkPMFloat<1>(1,0,0,0) + colors * SkPMFloat<1>(0,1,1,1);
 }
 #undef XFERMODE
 
@@ -234,7 +234,7 @@ private:
 
 class SkPMFloatXfermode : public SkProcCoeffXfermode {
 public:
-    typedef SkPMFloat (SK_VECTORCALL *ProcF)(SkPMFloat, SkPMFloat);
+    typedef SkPMFloat<1> (SK_VECTORCALL *ProcF)(SkPMFloat<1>, SkPMFloat<1>);
     SkPMFloatXfermode(const ProcCoeff& rec, SkXfermode::Mode mode, ProcF procf)
         : INHERITED(rec, mode)
         , fProcF(procf) {}
@@ -257,15 +257,15 @@ public:
 
 private:
     inline SkPMColor xfer32(SkPMColor dst, SkPMColor src) const {
-        return fProcF(SkPMFloat(dst), SkPMFloat(src)).round();
+        return fProcF(SkPMFloat<1>(dst), SkPMFloat<1>(src)).round();
     }
 
     inline SkPMColor xfer32(SkPMColor dst, SkPMColor src, SkAlpha aa) const {
-        SkPMFloat s(src),
-                  d(dst),
-                  b(fProcF(d,s));
+        SkPMFloat<1> s(src),
+                     d(dst),
+                     b(fProcF(d,s));
         // We do aa in full float precision before going back down to bytes, because we can!
-        SkPMFloat a = Sk4f(aa) * Sk4f(1.0f/255);
+        SkPMFloat<1> a = Sk4f(aa) * Sk4f(1.0f/255);
         b = b*a + d*(Sk4f(1)-a);
         return b.round();
     }