hide virtual and rename to onMakeComposed

Bug: skia:
Change-Id: Ic18ee2af3273f81ebec9c9031162e808186c0acd
Reviewed-on: https://skia-review.googlesource.com/108300
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/gm/color4f.cpp b/gm/color4f.cpp
index b1ec0bf..792f7d5 100644
--- a/gm/color4f.cpp
+++ b/gm/color4f.cpp
@@ -35,14 +35,13 @@
 static sk_sp<SkColorFilter> make_cf1() {
     SkColorMatrix cm;
     cm.setSaturation(0.75f);
-    auto a(SkColorFilter::MakeMatrixFilterRowMajor255(cm.fMat));
+    auto a = SkColorFilter::MakeMatrixFilterRowMajor255(cm.fMat);
     // CreateComposedFilter will try to concat these two matrices, resulting in a single
     // filter (which is good for speed). For this test, we want to force a real compose of
     // these two, so our inner filter has a scale-up, which disables the optimization of
     // combining the two matrices.
     cm.setScale(1.1f, 0.9f, 1);
-    auto b(SkColorFilter::MakeMatrixFilterRowMajor255(cm.fMat));
-    return SkColorFilter::MakeComposeFilter(a, b);
+    return a->makeComposed(SkColorFilter::MakeMatrixFilterRowMajor255(cm.fMat));
 }
 
 static sk_sp<SkColorFilter> make_cf2() {