gm: use DEF_GM macro consistantly

Change-Id: I705180db106ec4515aaec5f347199b98b21976fa
Reviewed-on: https://skia-review.googlesource.com/c/186081
Auto-Submit: Hal Canary <halcanary@google.com>
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
diff --git a/gm/copyTo4444.cpp b/gm/copyTo4444.cpp
index ec9b726..bdc2fe6 100644
--- a/gm/copyTo4444.cpp
+++ b/gm/copyTo4444.cpp
@@ -50,8 +50,7 @@
 
 //////////////////////////////////////////////////////////////////////////////
 
-static GM* MyFactory(void*) { return new CopyTo4444GM; }
-static GMRegistry reg(MyFactory);
+DEF_GM( return new CopyTo4444GM; )
 
 }