diff --git a/api/rtp_transceiver_interface.h b/api/rtp_transceiver_interface.h
index b131f9e903..1531c7ff44 100644
--- a/api/rtp_transceiver_interface.h
+++ b/api/rtp_transceiver_interface.h
@@ -153,45 +153,20 @@ class RTC_EXPORT RtpTransceiverInterface : public rtc::RefCountInterface {
   // with SetHeaderExtensionsToNegotiate, or a default set if it has not been
   // called.
   // https://w3c.github.io/webrtc-extensions/#rtcrtptransceiver-interface
-  // TODO(crbug.com/1051821): remove old name after Chromium roll, make pure
-  // virtual again.
   virtual std::vector<RtpHeaderExtensionCapability>
-  GetHeaderExtensionsToNegotiate() const {
-    return {};
-  }
-  virtual std::vector<RtpHeaderExtensionCapability> HeaderExtensionsToOffer()
-      const {
-    return GetHeaderExtensionsToNegotiate();
-  }
+  GetHeaderExtensionsToNegotiate() const = 0;
 
   // Returns either the empty set if negotation has not yet
   // happened, or a vector of the negotiated header extensions.
   // https://w3c.github.io/webrtc-extensions/#rtcrtptransceiver-interface
-  // TODO(crbug.com/1051821): remove old name after Chromium roll, make pure
-  // virtual again.
   virtual std::vector<RtpHeaderExtensionCapability>
-  GetNegotiatedHeaderExtensions() const {
-    return {};
-  }
-  virtual std::vector<RtpHeaderExtensionCapability> HeaderExtensionsNegotiated()
-      const {
-    return GetNegotiatedHeaderExtensions();
-  }
+  GetNegotiatedHeaderExtensions() const = 0;
 
   // The SetHeaderExtensionsToNegotiate method modifies the next SDP negotiation
   // so that it negotiates use of header extensions which are not kStopped.
   // https://w3c.github.io/webrtc-extensions/#rtcrtptransceiver-interface
-  // TODO(crbug.com/1051821): remove old name after Chromium roll, make pure
-  // virtual again.
   virtual webrtc::RTCError SetHeaderExtensionsToNegotiate(
-      rtc::ArrayView<const RtpHeaderExtensionCapability> header_extensions) {
-    return RTCError::OK();
-  }
-  virtual webrtc::RTCError SetOfferedRtpHeaderExtensions(
-      rtc::ArrayView<const RtpHeaderExtensionCapability>
-          header_extensions_to_offer) {
-    return SetHeaderExtensionsToNegotiate(header_extensions_to_offer);
-  }
+      rtc::ArrayView<const RtpHeaderExtensionCapability> header_extensions) = 0;
 
  protected:
   ~RtpTransceiverInterface() override = default;
diff --git a/pc/rtp_transceiver.cc b/pc/rtp_transceiver.cc
index 8e5ea9f42c..b8fc370f69 100644
--- a/pc/rtp_transceiver.cc
+++ b/pc/rtp_transceiver.cc
@@ -745,7 +745,7 @@ bool IsMandatoryHeaderExtension(const std::string& uri) {
 
 RTCError RtpTransceiver::SetHeaderExtensionsToNegotiate(
     rtc::ArrayView<const RtpHeaderExtensionCapability> header_extensions) {
-  // https://w3c.github.io/webrtc-extensions/#methods
+  // https://w3c.github.io/webrtc-extensions/#dom-rtcrtptransceiver-setheaderextensionstonegotiate
   if (header_extensions.size() != header_extensions_to_negotiate_.size()) {
     return RTCError(RTCErrorType::INVALID_MODIFICATION,
                     "Size of extensions to negotiate does not match.");