Revert of Parse FlexFEC RTP headers in Call and add integration with BWE. (patchset #17 id:460001 of https://codereview.webrtc.org/2553863003/ )

Reason for revert:
Unexpected perf regressions.

Original issue's description:
> Parse FlexFEC RTP headers in Call and add integration with BWE.
>
> BUG=webrtc:5654
>
> Review-Url: https://codereview.webrtc.org/2553863003
> Cr-Commit-Position: refs/heads/master@{#15709}
> Committed: https://chromium.googlesource.com/external/webrtc/+/ab2ffa3b28b55ef359232723049fb88b2dcd807a

TBR=philipel@webrtc.org,stefan@webrtc.org,danilchap@webrtc.org,nisse@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:5654

Review-Url: https://codereview.webrtc.org/2589393002
Cr-Commit-Position: refs/heads/master@{#15727}
diff --git a/webrtc/call/call.cc b/webrtc/call/call.cc
index c7998b2..1c4b7b2 100644
--- a/webrtc/call/call.cc
+++ b/webrtc/call/call.cc
@@ -24,7 +24,6 @@
 #include "webrtc/base/checks.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/logging.h"
-#include "webrtc/base/optional.h"
 #include "webrtc/base/task_queue.h"
 #include "webrtc/base/thread_annotations.h"
 #include "webrtc/base/thread_checker.h"
@@ -40,8 +39,6 @@
 #include "webrtc/modules/rtp_rtcp/include/flexfec_receiver.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_header_parser.h"
 #include "webrtc/modules/rtp_rtcp/source/byte_io.h"
-#include "webrtc/modules/rtp_rtcp/source/rtp_header_extension.h"
-#include "webrtc/modules/rtp_rtcp/source/rtp_packet_received.h"
 #include "webrtc/modules/utility/include/process_thread.h"
 #include "webrtc/system_wrappers/include/clock.h"
 #include "webrtc/system_wrappers/include/cpu_info.h"
@@ -110,8 +107,6 @@
   // Implements RecoveredPacketReceiver.
   bool OnRecoveredPacket(const uint8_t* packet, size_t length) override;
 
-  void NotifyBweOfReceivedPacket(const RtpPacketReceived& packet);
-
   void SetBitrateConfig(
       const webrtc::Call::Config::BitrateConfig& bitrate_config) override;
 
@@ -159,11 +154,6 @@
       return nullptr;
   }
 
-  rtc::Optional<RtpPacketReceived> ParseRtpPacket(const uint8_t* packet,
-                                                  size_t length,
-                                                  const PacketTime& packet_time)
-      SHARED_LOCKS_REQUIRED(receive_crit_);
-
   void UpdateSendHistograms() EXCLUSIVE_LOCKS_REQUIRED(&bitrate_crit_);
   void UpdateReceiveHistograms();
   void UpdateHistograms();
@@ -202,14 +192,6 @@
   std::map<std::string, AudioReceiveStream*> sync_stream_mapping_
       GUARDED_BY(receive_crit_);
 
-  // Registered RTP header extensions for each stream.
-  // Note that RTP header extensions are negotiated per track ("m= line") in the
-  // SDP, but we have no notion of tracks at the Call level. We therefore store
-  // the RTP header extensions per SSRC instead, which leads to some storage
-  // overhead.
-  std::map<uint32_t, RtpHeaderExtensionMap> received_rtp_header_extensions_
-      GUARDED_BY(receive_crit_);
-
   std::unique_ptr<RWLockWrapper> send_crit_;
   // Audio and Video send streams are owned by the client that creates them.
   std::map<uint32_t, AudioSendStream*> audio_send_ssrcs_ GUARDED_BY(send_crit_);
@@ -363,29 +345,6 @@
   Trace::ReturnTrace();
 }
 
-rtc::Optional<RtpPacketReceived> Call::ParseRtpPacket(
-    const uint8_t* packet,
-    size_t length,
-    const PacketTime& packet_time) {
-  RtpPacketReceived parsed_packet;
-  if (!parsed_packet.Parse(packet, length))
-    return rtc::Optional<RtpPacketReceived>();
-
-  auto it = received_rtp_header_extensions_.find(parsed_packet.Ssrc());
-  if (it != received_rtp_header_extensions_.end())
-    parsed_packet.IdentifyExtensions(it->second);
-
-  int64_t arrival_time_ms;
-  if (packet_time.timestamp != -1) {
-    arrival_time_ms = (packet_time.timestamp + 500) / 1000;
-  } else {
-    arrival_time_ms = clock_->TimeInMilliseconds();
-  }
-  parsed_packet.set_arrival_time_ms(arrival_time_ms);
-
-  return rtc::Optional<RtpPacketReceived>(std::move(parsed_packet));
-}
-
 void Call::UpdateHistograms() {
   RTC_HISTOGRAM_COUNTS_100000(
       "WebRTC.Call.LifetimeInSeconds",
@@ -700,40 +659,25 @@
     const FlexfecReceiveStream::Config& config) {
   TRACE_EVENT0("webrtc", "Call::CreateFlexfecReceiveStream");
   RTC_DCHECK(configuration_thread_checker_.CalledOnValidThread());
-
-  RecoveredPacketReceiver* recovered_packet_receiver = this;
   FlexfecReceiveStreamImpl* receive_stream =
-      new FlexfecReceiveStreamImpl(config, recovered_packet_receiver);
+      new FlexfecReceiveStreamImpl(config, this);
 
   {
     WriteLockScoped write_lock(*receive_crit_);
-
-    RTC_DCHECK(flexfec_receive_streams_.find(receive_stream) ==
-               flexfec_receive_streams_.end());
-    flexfec_receive_streams_.insert(receive_stream);
-
     for (auto ssrc : config.protected_media_ssrcs)
       flexfec_receive_ssrcs_media_.insert(std::make_pair(ssrc, receive_stream));
-
     RTC_DCHECK(flexfec_receive_ssrcs_protection_.find(config.remote_ssrc) ==
                flexfec_receive_ssrcs_protection_.end());
     flexfec_receive_ssrcs_protection_[config.remote_ssrc] = receive_stream;
-
-    RTC_DCHECK(received_rtp_header_extensions_.find(config.remote_ssrc) ==
-               received_rtp_header_extensions_.end());
-    RtpHeaderExtensionMap rtp_header_extensions(config.rtp_header_extensions);
-    received_rtp_header_extensions_[config.remote_ssrc] = rtp_header_extensions;
+    flexfec_receive_streams_.insert(receive_stream);
   }
-
   // TODO(brandtr): Store config in RtcEventLog here.
-
   return receive_stream;
 }
 
 void Call::DestroyFlexfecReceiveStream(FlexfecReceiveStream* receive_stream) {
   TRACE_EVENT0("webrtc", "Call::DestroyFlexfecReceiveStream");
   RTC_DCHECK(configuration_thread_checker_.CalledOnValidThread());
-
   RTC_DCHECK(receive_stream != nullptr);
   // There exist no other derived classes of FlexfecReceiveStream,
   // so this downcast is safe.
@@ -741,19 +685,8 @@
       static_cast<FlexfecReceiveStreamImpl*>(receive_stream);
   {
     WriteLockScoped write_lock(*receive_crit_);
-
-    uint32_t ssrc = receive_stream_impl->GetConfig().remote_ssrc;
-    received_rtp_header_extensions_.erase(ssrc);
-
     // Remove all SSRCs pointing to the FlexfecReceiveStreamImpl to be
     // destroyed.
-    auto prot_it = flexfec_receive_ssrcs_protection_.begin();
-    while (prot_it != flexfec_receive_ssrcs_protection_.end()) {
-      if (prot_it->second == receive_stream_impl)
-        prot_it = flexfec_receive_ssrcs_protection_.erase(prot_it);
-      else
-        ++prot_it;
-    }
     auto media_it = flexfec_receive_ssrcs_media_.begin();
     while (media_it != flexfec_receive_ssrcs_media_.end()) {
       if (media_it->second == receive_stream_impl)
@@ -761,10 +694,15 @@
       else
         ++media_it;
     }
-
+    auto prot_it = flexfec_receive_ssrcs_protection_.begin();
+    while (prot_it != flexfec_receive_ssrcs_protection_.end()) {
+      if (prot_it->second == receive_stream_impl)
+        prot_it = flexfec_receive_ssrcs_protection_.erase(prot_it);
+      else
+        ++prot_it;
+    }
     flexfec_receive_streams_.erase(receive_stream_impl);
   }
-
   delete receive_stream_impl;
 }
 
@@ -1138,21 +1076,13 @@
     if (it != video_receive_ssrcs_.end()) {
       received_bytes_per_second_counter_.Add(static_cast<int>(length));
       received_video_bytes_per_second_counter_.Add(static_cast<int>(length));
-      // TODO(brandtr): Notify the BWE of received media packets here.
       auto status = it->second->DeliverRtp(packet, length, packet_time)
                         ? DELIVERY_OK
                         : DELIVERY_PACKET_ERROR;
-      // Deliver media packets to FlexFEC subsystem. RTP header extensions need
-      // not be parsed, as FlexFEC is oblivious to the semantic meaning of the
-      // packet contents beyond the 12 byte RTP base header. The BWE is fed
-      // information about these media packets from the regular media pipeline.
-      rtc::Optional<RtpPacketReceived> parsed_packet =
-          ParseRtpPacket(packet, length, packet_time);
-      if (parsed_packet) {
-        auto it_bounds = flexfec_receive_ssrcs_media_.equal_range(ssrc);
-        for (auto it = it_bounds.first; it != it_bounds.second; ++it)
-          it->second->AddAndProcessReceivedPacket(*parsed_packet);
-      }
+      // Deliver media packets to FlexFEC subsystem.
+      auto it_bounds = flexfec_receive_ssrcs_media_.equal_range(ssrc);
+      for (auto it = it_bounds.first; it != it_bounds.second; ++it)
+        it->second->AddAndProcessReceivedPacket(packet, length);
       if (status == DELIVERY_OK)
         event_log_->LogRtpHeader(kIncomingPacket, media_type, packet, length);
       return status;
@@ -1161,18 +1091,12 @@
   if (media_type == MediaType::ANY || media_type == MediaType::VIDEO) {
     auto it = flexfec_receive_ssrcs_protection_.find(ssrc);
     if (it != flexfec_receive_ssrcs_protection_.end()) {
-      rtc::Optional<RtpPacketReceived> parsed_packet =
-          ParseRtpPacket(packet, length, packet_time);
-      if (parsed_packet) {
-        NotifyBweOfReceivedPacket(*parsed_packet);
-        auto status =
-            it->second->AddAndProcessReceivedPacket(std::move(*parsed_packet))
-                ? DELIVERY_OK
-                : DELIVERY_PACKET_ERROR;
-        if (status == DELIVERY_OK)
-          event_log_->LogRtpHeader(kIncomingPacket, media_type, packet, length);
-        return status;
-      }
+      auto status = it->second->AddAndProcessReceivedPacket(packet, length)
+                        ? DELIVERY_OK
+                        : DELIVERY_PACKET_ERROR;
+      if (status == DELIVERY_OK)
+        event_log_->LogRtpHeader(kIncomingPacket, media_type, packet, length);
+      return status;
     }
   }
   return DELIVERY_UNKNOWN_SSRC;
@@ -1204,12 +1128,5 @@
   return it->second->OnRecoveredPacket(packet, length);
 }
 
-void Call::NotifyBweOfReceivedPacket(const RtpPacketReceived& packet) {
-  RTPHeader header;
-  packet.GetHeader(&header);
-  congestion_controller_->OnReceivedPacket(packet.arrival_time_ms(),
-                                           packet.payload_size(), header);
-}
-
 }  // namespace internal
 }  // namespace webrtc