Make requesting SDES available only on Fuchsia builds

Bug: webrtc:11066
Change-Id: I0707cf63064830a55db31e883dc7b15aa675950b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/257900
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36438}
diff --git a/api/peer_connection_interface.h b/api/peer_connection_interface.h
index 2f8e401..a9026d9 100644
--- a/api/peer_connection_interface.h
+++ b/api/peer_connection_interface.h
@@ -457,11 +457,14 @@
     // Use new combined audio/video bandwidth estimation?
     absl::optional<bool> combined_audio_video_bwe;
 
+#if defined(WEBRTC_FUCHSIA)
+    // TODO(bugs.webrtc.org/11066): Remove entirely once Fuchsia does not use.
     // TODO(bugs.webrtc.org/9891) - Move to crypto_options
     // Can be used to disable DTLS-SRTP. This should never be done, but can be
     // useful for testing purposes, for example in setting up a loopback call
     // with a single PeerConnection.
     absl::optional<bool> enable_dtls_srtp;
+#endif
 
     /////////////////////////////////////////////////
     // The below fields are not part of the standard.