Add test for processor->resource ref/io counts

Change-Id: I63a8cb9f1564bfc15ef98121b77946a647c79f32
Reviewed-on: https://skia-review.googlesource.com/6814
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
diff --git a/gn/tests.gni b/gn/tests.gni
index 95e1a79..65b79ab 100644
--- a/gn/tests.gni
+++ b/gn/tests.gni
@@ -160,6 +160,7 @@
   "$_tests/PointTest.cpp",
   "$_tests/PremulAlphaRoundTripTest.cpp",
   "$_tests/PrimitiveProcessorTest.cpp",
+  "$_tests/ProcessorTest.cpp",
   "$_tests/ProxyConversionTest.cpp",
   "$_tests/ProxyRefTest.cpp",
   "$_tests/ProxyTest.cpp",