Add VideoSendStream::Config::EncoderSettings::experiment_cpu_load_estimator.

And wire it up to methods on RTCConfiguration, via MediaConfig::Video.

Bug: webrtc:8504
Change-Id: I30805ee20c11d1d2fe552eb81f16d514db0ba4a8
Reviewed-on: https://webrtc-review.googlesource.com/39786
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21670}
diff --git a/call/video_send_stream.h b/call/video_send_stream.h
index a3c6f4f..cb83176 100644
--- a/call/video_send_stream.h
+++ b/call/video_send_stream.h
@@ -131,6 +131,10 @@
       // 30fps (for example) exactly.
       bool full_overuse_time = false;
 
+      // Enables the new method to estimate the cpu load from encoding, used for
+      // cpu adaptation.
+      bool experiment_cpu_load_estimator = false;
+
       // Uninitialized VideoEncoder instance to be used for encoding. Will be
       // initialized from inside the VideoSendStream.
       VideoEncoder* encoder = nullptr;