Properly report number of quality downscales in stats.

webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc

Index: webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc
diff --git a/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc b/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc
index 6026cb31d2b0c29972bcf897854755dfabd1396a..69b1ff13aaf93f6f67e73dd78d5c66abc3ab7ce6 100644
--- a/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc
+++ b/webrtc/modules/video_coding/codecs/vp8/simulcast_encoder_adapter.cc
@@ -464,7 +464,7 @@ bool SimulcastEncoderAdapter::SupportsNativeHandle() const {
 VideoEncoder::ScalingSettings SimulcastEncoderAdapter::GetScalingSettings()
     const {
   // Turn off quality scaling for simulcast.
-  if (NumberOfStreams(codec_) != 1)
+  if (NumberOfStreams(codec_) != 1 || streaminfos_.size() != 1)

[stefan-webrtc, 2016/12/19 12:12:00]

Not obvious to me why this is needed. Could you elaborate?

[kthelgason, 2016/12/19 12:18:18]

This is actually not needed currently, but I ran into a crash here when testing
and decided to add a guard. If this method is called before the encoder is
initialized |streaminfos_| will have 0 size.

[stefan-webrtc, 2016/12/19 12:21:25]

Ok, maybe we should write

if (!Initialized() || NumberOfStreams(codec)_ != 1)

so that it's clear why we have to check streaminfos?

     return VideoEncoder::ScalingSettings(false);
   return streaminfos_[0].encoder->GetScalingSettings();
 }