GN target for test_packet_masks_metrics.

webrtc/modules/rtp_rtcp/BUILD.gn

Index: webrtc/modules/rtp_rtcp/BUILD.gn
diff --git a/webrtc/modules/rtp_rtcp/BUILD.gn b/webrtc/modules/rtp_rtcp/BUILD.gn
index 39aa1507e5c658d71901819434ed3414432c43fa..2abb025994fce9552e014a534f9805da36b0e327 100644
--- a/webrtc/modules/rtp_rtcp/BUILD.gn
+++ b/webrtc/modules/rtp_rtcp/BUILD.gn
@@ -180,3 +180,20 @@ source_set("rtp_rtcp") {
     ]
   }
 }
+
+if (rtc_include_tests) {
+  executable("test_packet_masks_metrics") {
+    testonly = true
+
+    sources = [
+      "test/testFec/average_residual_loss_xor_codes.h",
+      "test/testFec/test_packet_masks_metrics.cc",
+    ]
+
+    deps = [
+      ":rtp_rtcp",
+      "//testing/gtest",
+      "//webrtc/test:test_support_main",
+    ]
+  }  # test_packet_masks_metrics
+}