Implement Sk4f min/max

Bug: skia:
Change-Id: Icf235dea81e9f125c1c8590ec87cb3591393036c
Reviewed-on: https://skia-review.googlesource.com/120281
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
diff --git a/tests/SkNxTest.cpp b/tests/SkNxTest.cpp
index c27b88c..c82f39d 100644
--- a/tests/SkNxTest.cpp
+++ b/tests/SkNxTest.cpp
@@ -466,6 +466,18 @@
     REPORTER_ASSERT(r, dst[7] == 7);
 }
 
+DEF_TEST(Sk4f_minmax, r) {
+    REPORTER_ASSERT(r,  3 == Sk4f(0,1,2,3).max());
+    REPORTER_ASSERT(r,  2 == Sk4f(1,-5,2,-1).max());
+    REPORTER_ASSERT(r, -1 == Sk4f(-2,-1,-6,-3).max());
+    REPORTER_ASSERT(r,  3 == Sk4f(3,2,1,0).max());
+
+    REPORTER_ASSERT(r,  0 == Sk4f(0,1,2,3).min());
+    REPORTER_ASSERT(r, -5 == Sk4f(1,-5,2,-1).min());
+    REPORTER_ASSERT(r, -6 == Sk4f(-2,-1,-6,-3).min());
+    REPORTER_ASSERT(r,  0 == Sk4f(3,2,1,0).min());
+}
+
 DEF_TEST(SkNf_anyTrue_allTrue, r) {
     REPORTER_ASSERT(r,  (Sk2f{1,2} < Sk2f{3,4}).anyTrue());
     REPORTER_ASSERT(r,  (Sk2f{1,2} < Sk2f{3,4}).allTrue());