Add Sk4f::ToBytes(uint8_t[16], Sk4f, Sk4f, Sk4f, Sk4f)

bench/Sk4fBench.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Benchmark.h"
 #include "SkColor.h"
 #include "SkNx.h"
@@ skipping 44 matching lines @@
              dx(0.002f),
              dcdx(dc*dx),
              dcdx4(dcdx+dcdx+dcdx+dcdx);
 
         for (int n = 0; n < loops; n++) {
             Sk4f a = c0 + dc*fx + Sk4f(0.5f),  // add an extra 0.5f to get rounding for free.
                  b = a + dcdx,
                  c = b + dcdx,
                  d = c + dcdx;
             for (size_t i = 0; i < SK_ARRAY_COUNT(fDevice); i += 4) {
-                a.toBytes((uint8_t*)(fDevice+i+0));
-                b.toBytes((uint8_t*)(fDevice+i+1));
-                c.toBytes((uint8_t*)(fDevice+i+2));
-                d.toBytes((uint8_t*)(fDevice+i+3));
+                Sk4f::ToBytes((uint8_t*)(fDevice+i), a, b, c, d);
                 a = a + dcdx4;
                 b = b + dcdx4;
                 c = c + dcdx4;
                 d = d + dcdx4;
             }
         }
     }
 };
 DEF_BENCH(return new Sk4fGradientBench;)