Do not support frame tracking id extension in production

Pushing it to the list of extensions to negotiate could result
in enabling it in production.

BUG=None

Change-Id: I98599e9fbac7e2b81b3f2ad0c7759bb052d9d9d1
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/306101
Commit-Queue: Philipp Hancke <phancke@microsoft.com>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#40250}
diff --git a/media/engine/webrtc_video_engine.cc b/media/engine/webrtc_video_engine.cc
index 971cee3..1637451 100644
--- a/media/engine/webrtc_video_engine.cc
+++ b/media/engine/webrtc_video_engine.cc
@@ -912,12 +912,11 @@
           ? webrtc::RtpTransceiverDirection::kSendRecv
           : webrtc::RtpTransceiverDirection::kStopped);
 
-  result.emplace_back(
-      webrtc::RtpExtension::kVideoFrameTrackingIdUri, id++,
-      IsEnabled(trials_, "WebRTC-VideoFrameTrackingIdAdvertised")
-          ? webrtc::RtpTransceiverDirection::kSendRecv
-          : webrtc::RtpTransceiverDirection::kStopped);
-
+  // VideoFrameTrackingId is a test-only extension.
+  if (IsEnabled(trials_, "WebRTC-VideoFrameTrackingIdAdvertised")) {
+    result.emplace_back(webrtc::RtpExtension::kVideoFrameTrackingIdUri, id++,
+                        webrtc::RtpTransceiverDirection::kSendRecv);
+  }
   return result;
 }