Delete obsolete unused rtp header extension conversion

Bug: None
Change-Id: Ice78a35502465c5f03ef66ee73788405fd4f7356
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/163025
Reviewed-by: Steve Anton <steveanton@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30188}
diff --git a/api/rtp_parameters.h b/api/rtp_parameters.h
index 342ef0f..2ce0b48 100644
--- a/api/rtp_parameters.h
+++ b/api/rtp_parameters.h
@@ -329,9 +329,6 @@
   bool encrypt = false;
 };
 
-// TODO(deadbeef): This is missing the "encrypt" flag, which is unimplemented.
-typedef RtpExtension RtpHeaderExtensionParameters;
-
 struct RTC_EXPORT RtpFecParameters {
   // If unset, a value is chosen by the implementation.
   // Works just like RtpEncodingParameters::ssrc.
@@ -590,7 +587,7 @@
 
   std::vector<RtpCodecParameters> codecs;
 
-  std::vector<RtpHeaderExtensionParameters> header_extensions;
+  std::vector<RtpExtension> header_extensions;
 
   std::vector<RtpEncodingParameters> encodings;