Enable GN check in webrtc/stats

BUG=webrtc:6828
NOTRY=True

Review-Url: https://codereview.webrtc.org/2720533002
Cr-Commit-Position: refs/heads/master@{#16881}
diff --git a/.gn b/.gn
index 77394c6..db578de 100644
--- a/.gn
+++ b/.gn
@@ -40,7 +40,7 @@
   "//webrtc/modules/video_coding/*",
   "//webrtc/modules/video_processing/*",
   "//webrtc/modules/remote_bitrate_estimator/*",
-  "//webrtc/stats:rtc_stats",
+  "//webrtc/stats/*",
   "//webrtc/voice_engine",
   "//webrtc/voice_engine:audio_coder",
   "//webrtc/voice_engine:file_player",
diff --git a/webrtc/stats/BUILD.gn b/webrtc/stats/BUILD.gn
index 85ba21d..4a2f578 100644
--- a/webrtc/stats/BUILD.gn
+++ b/webrtc/stats/BUILD.gn
@@ -57,7 +57,10 @@
     deps = [
       ":rtc_stats",
       ":rtc_stats_test_utils",
+      "../api:rtc_stats_api",
+      "../base:rtc_base_approved",
       "../base:rtc_base_tests_main",
+      "../base:rtc_base_tests_utils",
       "../system_wrappers:metrics_default",
       "//testing/gmock",
     ]