Outline SkImageFilter Make methods

include/effects/SkTestImageFilters.h

Index: include/effects/SkTestImageFilters.h
diff --git a/include/effects/SkTestImageFilters.h b/include/effects/SkTestImageFilters.h
index 0f89759c1c8dd141d059945b5097046f52c45230..4aa30083ddaef8dd631ca147697bccdc70c4f144 100644
--- a/include/effects/SkTestImageFilters.h
+++ b/include/effects/SkTestImageFilters.h
@@ -14,16 +14,7 @@
 // Fun mode that scales down (only) and then scales back up to look pixelated
 class SK_API SkDownSampleImageFilter : public SkImageFilter {
 public:
-    static sk_sp<SkImageFilter> Make(SkScalar scale, sk_sp<SkImageFilter> input) {
-        if (!SkScalarIsFinite(scale)) {
-            return nullptr;
-        }
-        // we don't support scale in this range
-        if (scale > SK_Scalar1 || scale <= 0) {
-            return nullptr;
-        }
-        return sk_sp<SkImageFilter>(new SkDownSampleImageFilter(scale, std::move(input)));
-    }
+    static sk_sp<SkImageFilter> Make(SkScalar scale, sk_sp<SkImageFilter> input);
 
     SK_TO_STRING_OVERRIDE()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkDownSampleImageFilter)