Extract common simulcast logic from VP8 wrapper and simulcast adapter

webrtc/video/vie_encoder.cc

Index: webrtc/video/vie_encoder.cc
diff --git a/webrtc/video/vie_encoder.cc b/webrtc/video/vie_encoder.cc
index 8240f9bfa635a32fa7cdd0b0cb0e47a6a0cdc2e0..e0240b0b35696f9da35a664c56dc452231db00c6 100644
--- a/webrtc/video/vie_encoder.cc
+++ b/webrtc/video/vie_encoder.cc
@@ -25,6 +25,7 @@
 #include "webrtc/modules/video_coding/include/video_codec_interface.h"
 #include "webrtc/modules/video_coding/include/video_coding.h"
 #include "webrtc/modules/video_coding/include/video_coding_defines.h"
+#include "webrtc/modules/video_coding/utility/simulcast_state.h"
 #include "webrtc/system_wrappers/include/clock.h"
 #include "webrtc/system_wrappers/include/metrics.h"
 #include "webrtc/system_wrappers/include/tick_util.h"
@@ -38,28 +39,6 @@ namespace webrtc {
 static const float kStopPaddingThresholdMs = 2000;
 static const int kMinKeyFrameRequestIntervalMs = 300;
 
-std::vector<uint32_t> AllocateStreamBitrates(
-    uint32_t total_bitrate,
-    const SimulcastStream* stream_configs,
-    size_t number_of_streams) {
-  if (number_of_streams == 0) {
-    std::vector<uint32_t> stream_bitrates(1, 0);
-    stream_bitrates[0] = total_bitrate;
-    return stream_bitrates;
-  }
-  std::vector<uint32_t> stream_bitrates(number_of_streams, 0);
-  uint32_t bitrate_remainder = total_bitrate;
-  for (size_t i = 0; i < stream_bitrates.size() && bitrate_remainder > 0; ++i) {
-    if (stream_configs[i].maxBitrate * 1000 > bitrate_remainder) {
-      stream_bitrates[i] = bitrate_remainder;
-    } else {
-      stream_bitrates[i] = stream_configs[i].maxBitrate * 1000;
-    }
-    bitrate_remainder -= stream_bitrates[i];
-  }
-  return stream_bitrates;
-}
-
 class QMVideoSettingsCallback : public VCMQMSettingsCallback {
  public:
   explicit QMVideoSettingsCallback(VideoProcessing* vpm);
@@ -183,6 +162,8 @@ void ViEEncoder::SetEncoder(const webrtc::VideoCodec& video_codec,
     encoder_config_ = video_codec;
     encoder_paused_ = true;
     min_transmit_bitrate_bps_ = min_transmit_bitrate_bps;
+    if (encoder_config_.codecType == kVideoCodecVP8)
+      simulcast_rates_.reset(new SimulcastState(encoder_config_));
   }
 
   size_t max_data_payload_length = send_payload_router_->MaxPayloadLength();
@@ -498,18 +479,24 @@ void ViEEncoder::OnBitrateUpdated(uint32_t bitrate_bps,
   bool video_is_suspended = video_sender_.VideoSuspended();
   bool video_suspension_changed;
   VideoCodec send_codec;
+  std::vector<uint32_t> stream_bitrates;
   {
     rtc::CritScope lock(&data_cs_);
     last_observed_bitrate_bps_ = bitrate_bps;
     video_suspension_changed = video_suspended_ != video_is_suspended;
     video_suspended_ = video_is_suspended;
     send_codec = encoder_config_;
+
+    if (simulcast_rates_.get()) {
+      simulcast_rates_->AllocateBitrate(bitrate_bps);
+      for (auto stream : *simulcast_rates_)
+        stream_bitrates.push_back(stream.allocated_rate_kbps * 1000);
+    } else {
+      stream_bitrates.push_back(bitrate_bps);
+    }
   }
 
-  SimulcastStream* stream_configs = send_codec.simulcastStream;
   // Allocate the bandwidth between the streams.
-  std::vector<uint32_t> stream_bitrates = AllocateStreamBitrates(
-      bitrate_bps, stream_configs, send_codec.numberOfSimulcastStreams);
   send_payload_router_->SetTargetSendBitrates(stream_bitrates);
 
   if (!video_suspension_changed)