Revert "Use RtpSenderEgress directly instead of via RTPSender"

This reverts commit b533010bc66a0628c8efa4d6c3dd60b8336f2736.

Reason for revert: Breaks downstream tests.

Original change's description:
> Use RtpSenderEgress directly instead of via RTPSender
> 
> Bug: webrtc:11036
> Change-Id: Ida4e8bc705ae43ceb1b131114707b30d10ba8642
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158521
> Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
> Commit-Queue: Erik Språng <sprang@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#29626}

TBR=ilnik@webrtc.org,sprang@webrtc.org

Change-Id: Ib3354f6907d21462a8ad0c37eb8f6e94c48af217
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:11036
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158526
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29627}
diff --git a/modules/rtp_rtcp/source/rtp_rtcp_impl.h b/modules/rtp_rtcp/source/rtp_rtcp_impl.h
index 0edf1ba..01ef03a 100644
--- a/modules/rtp_rtcp/source/rtp_rtcp_impl.h
+++ b/modules/rtp_rtcp/source/rtp_rtcp_impl.h
@@ -29,10 +29,8 @@
 #include "modules/rtp_rtcp/source/rtcp_packet/tmmb_item.h"
 #include "modules/rtp_rtcp/source/rtcp_receiver.h"
 #include "modules/rtp_rtcp/source/rtcp_sender.h"
-#include "modules/rtp_rtcp/source/rtp_packet_history.h"
 #include "modules/rtp_rtcp/source/rtp_packet_to_send.h"
 #include "modules/rtp_rtcp/source/rtp_sender.h"
-#include "modules/rtp_rtcp/source/rtp_sender_egress.h"
 #include "rtc_base/critical_section.h"
 #include "rtc_base/gtest_prod_util.h"
 
@@ -280,12 +278,8 @@
  protected:
   bool UpdateRTCPReceiveInformationTimers();
 
-  RTPSender* rtp_sender() {
-    return rtp_sender_ ? &rtp_sender_->packet_generator_ : nullptr;
-  }
-  const RTPSender* rtp_sender() const {
-    return rtp_sender_ ? &rtp_sender_->packet_generator_ : nullptr;
-  }
+  RTPSender* rtp_sender() { return rtp_sender_.get(); }
+  const RTPSender* rtp_sender() const { return rtp_sender_.get(); }
 
   RTCPSender* rtcp_sender() { return &rtcp_sender_; }
   const RTCPSender* rtcp_sender() const { return &rtcp_sender_; }
@@ -299,26 +293,12 @@
   FRIEND_TEST_ALL_PREFIXES(RtpRtcpImplTest, Rtt);
   FRIEND_TEST_ALL_PREFIXES(RtpRtcpImplTest, RttForReceiverOnly);
 
-  struct RtpSenderContext {
-    explicit RtpSenderContext(const RtpRtcp::Configuration& config);
-    // Storage of packets, for retransmissions and padding, if applicable.
-    RtpPacketHistory packet_history_;
-    // Handles final time timestamping/stats/etc and handover to Transport.
-    RtpSenderEgress packet_sender_;
-    // If no paced sender configured, this class will be used to pass packets
-    // from |packet_generator_| to |packet_sender_|.
-    RtpSenderEgress::NonPacedPacketSender non_paced_sender_;
-    // Handles creation of RTP packets to be sent.
-    RTPSender packet_generator_;
-  };
-
   void set_rtt_ms(int64_t rtt_ms);
   int64_t rtt_ms() const;
 
   bool TimeToSendFullNackList(int64_t now) const;
 
-  std::unique_ptr<RtpSenderContext> rtp_sender_;
-
+  std::unique_ptr<RTPSender> rtp_sender_;
   RTCPSender rtcp_sender_;
   RTCPReceiver rtcp_receiver_;