Cleanup RtpHeaderExtensionMap removing use of two legacy functions

webrtc/modules/rtp_rtcp/source/rtp_header_parser.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include "webrtc/modules/rtp_rtcp/include/rtp_header_parser.h"
@@ skipping 35 matching lines @@
 
 bool RtpHeaderParserImpl::Parse(const uint8_t* packet,
                                 size_t length,
                                 RTPHeader* header) const {
   RtpUtility::RtpHeaderParser rtp_parser(packet, length);
   memset(header, 0, sizeof(*header));
 
   RtpHeaderExtensionMap map;
   {
     rtc::CritScope cs(&critical_section_);
-    rtp_header_extension_map_.GetCopy(&map);
+    map = rtp_header_extension_map_;
   }
 
   const bool valid_rtpheader = rtp_parser.Parse(header, &map);
   if (!valid_rtpheader) {
     return false;
   }
   return true;
 }
 
 bool RtpHeaderParserImpl::RegisterRtpHeaderExtension(RTPExtensionType type,
                                                      uint8_t id) {
   rtc::CritScope cs(&critical_section_);
-  return rtp_header_extension_map_.Register(type, id) == 0;
+  return rtp_header_extension_map_.RegisterByType(id, type);
 }
 
 bool RtpHeaderParserImpl::DeregisterRtpHeaderExtension(RTPExtensionType type) {
   rtc::CritScope cs(&critical_section_);
   return rtp_header_extension_map_.Deregister(type) == 0;
 }
 }  // namespace webrtc