Add unit test for SkDeferredDisplayLists (take 2)

Change-Id: I76a4c77d5b9418cb7fe677bd55ba32a2e336924d
Reviewed-on: https://skia-review.googlesource.com/79820
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/gn/tests.gni b/gn/tests.gni
index 23e4f83..eb20aab 100644
--- a/gn/tests.gni
+++ b/gn/tests.gni
@@ -47,8 +47,9 @@
   "$_tests/CTest.cpp",
   "$_tests/DashPathEffectTest.cpp",
   "$_tests/DataRefTest.cpp",
-  "$_tests/DequeTest.cpp",
   "$_tests/DefaultPathRendererTest.cpp",
+  "$_tests/DeferredDisplayListTest.cpp",
+  "$_tests/DequeTest.cpp",
   "$_tests/DetermineDomainModeTest.cpp",
   "$_tests/DeviceLooperTest.cpp",
   "$_tests/DeviceTest.cpp",