s/SkAutoTUnref/sk_sp/ in src/ part 1

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4480

Change-Id: I7d3219b02ad5094785e1b7635a9482e69aadbc8c
Reviewed-on: https://skia-review.googlesource.com/4480
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
diff --git a/src/codec/SkPngCodec.cpp b/src/codec/SkPngCodec.cpp
index 8297dd4..3cf972d 100644
--- a/src/codec/SkPngCodec.cpp
+++ b/src/codec/SkPngCodec.cpp
@@ -1084,7 +1084,7 @@
     }
 
     // Copy the color table to the client if they request kIndex8 mode.
-    copy_color_table(dstInfo, fColorTable, ctable, ctableCount);
+    copy_color_table(dstInfo, fColorTable.get(), ctable, ctableCount);
 
     this->initializeSwizzler(dstInfo, options);
     return true;