RtpRtcp allows to register header extension by name

webrtc/modules/rtp_rtcp/include/rtp_rtcp.h

Index: webrtc/modules/rtp_rtcp/include/rtp_rtcp.h
diff --git a/webrtc/modules/rtp_rtcp/include/rtp_rtcp.h b/webrtc/modules/rtp_rtcp/include/rtp_rtcp.h
index e0ace4c775d76c9df39d0d9a69954cb9c8b50df2..8a8ff9bc2a207c771dea837d2f3dd8b45b7cd990 100644
--- a/webrtc/modules/rtp_rtcp/include/rtp_rtcp.h
+++ b/webrtc/modules/rtp_rtcp/include/rtp_rtcp.h
@@ -12,6 +12,7 @@
 #define WEBRTC_MODULES_RTP_RTCP_INCLUDE_RTP_RTCP_H_
 
 #include <set>
+#include <string>
 #include <utility>
 #include <vector>
 
@@ -182,6 +183,9 @@ class RtpRtcp : public Module {
     virtual int32_t RegisterSendRtpHeaderExtension(RTPExtensionType type,
                                                    uint8_t id) = 0;
 
+    virtual bool RegisterRtpHeaderExtension(const std::string& type,
+                                            uint8_t id) = 0;
+
     virtual int32_t DeregisterSendRtpHeaderExtension(RTPExtensionType type) = 0;
 
     /*