Extract common simulcast logic from VP8 wrapper and simulcast adapter

webrtc/video/payload_router.h

Index: webrtc/video/payload_router.h
diff --git a/webrtc/video/payload_router.h b/webrtc/video/payload_router.h
index ce65bae6f81d150c8110a072b414e24e5e7eed77..c6575cfc26368b012e879f6aa08882b6e2decb97 100644
--- a/webrtc/video/payload_router.h
+++ b/webrtc/video/payload_router.h
@@ -18,6 +18,7 @@
 #include "webrtc/base/thread_annotations.h"
 #include "webrtc/common_types.h"
 #include "webrtc/config.h"
+#include "webrtc/modules/video_coding/utility/simulcast_state.h"
 #include "webrtc/video_encoder.h"
 #include "webrtc/system_wrappers/include/atomic32.h"
 
@@ -52,6 +53,8 @@ class PayloadRouter : public EncodedImageCallback {
 
   // Configures current target bitrate.
   void SetTargetSendBitrate(uint32_t bitrate_bps);
+  // Update simulcast configuration when reconfiguring encoders.
+  void UpdateSimulcastState(const SimulcastState& state);
 
   // Returns the maximum allowed data payload length, given the configured MTU
   // and RTP headers.
@@ -64,6 +67,7 @@ class PayloadRouter : public EncodedImageCallback {
   bool active_ GUARDED_BY(crit_);
   std::vector<VideoStream> streams_ GUARDED_BY(crit_);
   size_t num_sending_modules_ GUARDED_BY(crit_);
+  SimulcastState simulcast_state_ GUARDED_BY(crit_);
 
   // Rtp modules are assumed to be sorted in simulcast index order. Not owned.
   const std::vector<RtpRtcp*> rtp_modules_;