Refactoring PayloadRouter.

- Move PayloadRouter to RtpTransportControllerInterface.
- Move RetransmissionLimiter inside RtpTransportControllerSend from
  VideoSendStreamImpl.
- Move video RTP specifics into PayloadRouter, in particular ownership
  of the RTP modules.
- PayloadRouter now contains all video specific RTP code, and will be
  renamed in a follow-up to VideoRtpSender.
- Introduce VideoRtpSenderInterface.

Bug: webrtc:9517
Change-Id: I1c7b293fa6f9c320286c80533b3c584498034a38
Reviewed-on: https://webrtc-review.googlesource.com/88240
Commit-Queue: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24009}

modules/video_coding/media_opt_util.cc

@@ -29,6 +29,20 @@ static const int kPacketLossMax = 129;
 
 namespace media_optimization {
 
+VCMProtectionParameters::VCMProtectionParameters()
+    : rtt(0),
+      lossPr(0.0f),
+      bitRate(0.0f),
+      packetsPerFrame(0.0f),
+      packetsPerFrameKey(0.0f),
+      frameRate(0.0f),
+      keyFrameSize(0.0f),
+      fecRateDelta(0),
+      fecRateKey(0),
+      codecWidth(0),
+      codecHeight(0),
+      numLayers(1) {}
+
 VCMProtectionMethod::VCMProtectionMethod()
     : _effectivePacketLoss(0),
       _protectionFactorK(0),
@@ -40,6 +54,34 @@ VCMProtectionMethod::VCMProtectionMethod()
 
 VCMProtectionMethod::~VCMProtectionMethod() {}
 
+enum VCMProtectionMethodEnum VCMProtectionMethod::Type() const {
+  return _type;
+}
+
+uint8_t VCMProtectionMethod::RequiredPacketLossER() {
+  return _effectivePacketLoss;
+}
+
+uint8_t VCMProtectionMethod::RequiredProtectionFactorK() {
+  return _protectionFactorK;
+}
+
+uint8_t VCMProtectionMethod::RequiredProtectionFactorD() {
+  return _protectionFactorD;
+}
+
+bool VCMProtectionMethod::RequiredUepProtectionK() {
+  return _useUepProtectionK;
+}
+
+bool VCMProtectionMethod::RequiredUepProtectionD() {
+  return _useUepProtectionD;
+}
+
+int VCMProtectionMethod::MaxFramesFec() const {
+  return 1;
+}
+
 VCMNackFecMethod::VCMNackFecMethod(int64_t lowRttNackThresholdMs,
                                    int64_t highRttNackThresholdMs)
     : VCMFecMethod(),