Outline SkImageFilter Make methods

src/effects/SkComposeImageFilter.cpp

Index: src/effects/SkComposeImageFilter.cpp
diff --git a/src/effects/SkComposeImageFilter.cpp b/src/effects/SkComposeImageFilter.cpp
index e960f966c5c9de848b62ad4121f6b94a67685525..a54e53b67a727546e753f4a2c68b0da2926a68aa 100644
--- a/src/effects/SkComposeImageFilter.cpp
+++ b/src/effects/SkComposeImageFilter.cpp
@@ -11,6 +11,17 @@
 #include "SkSpecialImage.h"
 #include "SkWriteBuffer.h"
 
+sk_sp<SkImageFilter> SkComposeImageFilter::Make(sk_sp<SkImageFilter> outer,
+                                                sk_sp<SkImageFilter> inner) {
+    if (!outer) {
+        return inner;
+    }
+    if (!inner) {
+        return outer;
+    }
+    sk_sp<SkImageFilter> inputs[2] = { std::move(outer), std::move(inner) };
+    return sk_sp<SkImageFilter>(new SkComposeImageFilter(inputs));
+}
 
 SkRect SkComposeImageFilter::computeFastBounds(const SkRect& src) const {
     SkImageFilter* outer = this->getInput(0);