Move off SK_SUPPORT_LEGACY_DATA_FACTORIES.

This moves Skia code off of SK_SUPPORT_LEGACY_DATA_FACTORIES.
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2206633004

Review-Url: https://codereview.chromium.org/2206633004
diff --git a/dm/DMJsonWriter.cpp b/dm/DMJsonWriter.cpp
index 7bd8acd..79f308f 100644
--- a/dm/DMJsonWriter.cpp
+++ b/dm/DMJsonWriter.cpp
@@ -95,7 +95,7 @@
 }
 
 bool JsonWriter::ReadJson(const char* path, void(*callback)(BitmapResult)) {
-    SkAutoTUnref<SkData> json(SkData::NewFromFileName(path));
+    sk_sp<SkData> json(SkData::MakeFromFileName(path));
     if (!json) {
         return false;
     }