Revert of SSRC and RSID may only refer to one sink each in RtpDemuxer

webrtc/call/rtp_rtcp_demuxer_helper.h

 /*
  *  Copyright (c) 2017 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.
  */
 
 #ifndef WEBRTC_CALL_RTP_RTCP_DEMUXER_HELPER_H_
 #define WEBRTC_CALL_RTP_RTCP_DEMUXER_HELPER_H_
 
 #include <algorithm>
 #include <map>
 #include <utility>
 
 #include "webrtc/rtc_base/array_view.h"
 #include "webrtc/rtc_base/basictypes.h"
 #include "webrtc/rtc_base/optional.h"
 
 namespace webrtc {
 
-// TODO(eladalon): Remove this in the next CL.
 template <typename Container>
 bool MultimapAssociationExists(const Container& multimap,
                                const typename Container::key_type& key,
                                const typename Container::mapped_type& val) {
   auto it_range = multimap.equal_range(key);
   using Reference = typename Container::const_reference;
   return std::any_of(it_range.first, it_range.second,
                      [val](Reference elem) { return elem.second == val; });
 }
 
-// TODO(eladalon): Remove this in the next CL.
 template <typename Container, typename Value>
 size_t RemoveFromMultimapByValue(Container* multimap, const Value& value) {
   size_t count = 0;
   for (auto it = multimap->begin(); it != multimap->end();) {
     if (it->second == value) {
       it = multimap->erase(it);
       ++count;
     } else {
       ++it;
     }
   }
   return count;
 }
 
-template <typename Map, typename Value>
-size_t RemoveFromMapByValue(Map* map, const Value& value) {
-  size_t count = 0;
-  for (auto it = map->begin(); it != map->end();) {
-    if (it->second == value) {
-      it = map->erase(it);
-      ++count;
-    } else {
-      ++it;
-    }
-  }
-  return count;
-}
-
 template <typename Container, typename Key>
 bool ContainerHasKey(const Container& c, const Key& k) {
   return std::find(c.cbegin(), c.cend(), k) != c.cend();
 }
 
-// TODO(eladalon): Remove this in the next CL.
 template <typename Container>
 bool MultimapHasValue(const Container& c,
                       const typename Container::mapped_type& v) {
   auto predicate = [v](const typename Container::value_type& it) {
     return it.second == v;
   };
   return std::any_of(c.cbegin(), c.cend(), predicate);
 }
 
-template <typename Map>
-bool MapHasValue(const Map& map, const typename Map::mapped_type& value) {
-  auto predicate = [value](const typename Map::value_type& it) {
-    return it.second == value;
-  };
-  return std::any_of(map.cbegin(), map.cend(), predicate);
-}
-
 rtc::Optional<uint32_t> ParseRtcpPacketSenderSsrc(
     rtc::ArrayView<const uint8_t> packet);
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_CALL_RTP_RTCP_DEMUXER_HELPER_H_