Add test-only group id.

Bug: chromium:943076
Change-Id: Ife855fe59fe5e358bc94e4bb0da704ee2647dbd9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/129900
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Commit-Queue: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27356}
diff --git a/api/stats/rtc_stats.h b/api/stats/rtc_stats.h
index ed3765c..bb23490 100644
--- a/api/stats/rtc_stats.h
+++ b/api/stats/rtc_stats.h
@@ -184,6 +184,8 @@
 // determine if a stats member should be exposed or not. Multiple non-standard
 // stats members can share the same group ID so that they are exposed together.
 enum class NonStandardGroupId {
+  // Group ID used for testing purposes only.
+  kGroupIdForTesting,
   // I2E:
   // https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/hE2B1iItPDk
   kRtcAudioJitterBufferMaxPackets,
diff --git a/stats/rtc_stats_unittest.cc b/stats/rtc_stats_unittest.cc
index 1a948ba..b159977 100644
--- a/stats/rtc_stats_unittest.cc
+++ b/stats/rtc_stats_unittest.cc
@@ -340,7 +340,7 @@
 }
 
 TEST(RTCStatsTest, NonStandardGroupId) {
-  auto group_id = NonStandardGroupId::kRtcAudioJitterBufferMaxPackets;
+  auto group_id = NonStandardGroupId::kGroupIdForTesting;
   RTCNonStandardStatsMember<int32_t> with_group_id("stat", {group_id});
   std::vector<NonStandardGroupId> expected_ids({group_id});
   EXPECT_EQ(expected_ids, with_group_id.group_ids());