Enable setting the maximum bitrate limit in RtpSender.

webrtc/media/engine/webrtcvideoengine2.h

Index: webrtc/media/engine/webrtcvideoengine2.h
diff --git a/webrtc/media/engine/webrtcvideoengine2.h b/webrtc/media/engine/webrtcvideoengine2.h
index ccf753e9fc663bb6cec50bc7ea364b08df80adbf..b09f632bc6eee94af5795b784794093dfd77750b 100644
--- a/webrtc/media/engine/webrtcvideoengine2.h
+++ b/webrtc/media/engine/webrtcvideoengine2.h
@@ -145,6 +145,9 @@ class WebRtcVideoChannel2 : public VideoMediaChannel, public webrtc::Transport {
 
   bool SetSendParameters(const VideoSendParameters& params) override;
   bool SetRecvParameters(const VideoRecvParameters& params) override;
+  webrtc::RtpParameters GetRtpParameters(uint32_t ssrc) const override;
+  bool SetRtpParameters(uint32_t ssrc,
+                        const webrtc::RtpParameters& parameters) override;
   bool GetSendCodec(VideoCodec* send_codec) override;
   bool SetSend(bool send) override;
   bool SetVideoSend(uint32_t ssrc,
@@ -245,6 +248,7 @@ class WebRtcVideoChannel2 : public VideoMediaChannel, public webrtc::Transport {
     void SetOptions(const VideoOptions& options);
     // TODO(pbos): Move logic from SetOptions into this method.
     void SetSendParameters(const ChangedSendParameters& send_params);
+    bool SetRtpParameters(const webrtc::RtpParameters& parameters);
 
     void OnFrame(const cricket::VideoFrame& frame) override;
     bool SetCapturer(VideoCapturer* capturer);
@@ -254,6 +258,8 @@ class WebRtcVideoChannel2 : public VideoMediaChannel, public webrtc::Transport {
     void Start();
     void Stop();
 
+    webrtc::RtpParameters rtp_parameters() const { return rtp_parameters_; }
+
     // Implements webrtc::LoadObserver.
     void OnLoadUpdate(Load load) override;
 
@@ -338,6 +344,8 @@ class WebRtcVideoChannel2 : public VideoMediaChannel, public webrtc::Transport {
         const VideoCodec& codec) const EXCLUSIVE_LOCKS_REQUIRED(lock_);
     void SetDimensions(int width, int height)
         EXCLUSIVE_LOCKS_REQUIRED(lock_);
+    bool ValidateRtpParameters(const webrtc::RtpParameters& parameters);
+    void ApplyBitrateLimit(int max_bitrate_bps) EXCLUSIVE_LOCKS_REQUIRED(lock_);
 
     rtc::ThreadChecker thread_checker_;
     rtc::AsyncInvoker invoker_;
@@ -376,6 +384,9 @@ class WebRtcVideoChannel2 : public VideoMediaChannel, public webrtc::Transport {
     // The timestamp of the last frame received
     // Used to generate timestamp for the black frame when capturer is removed
     int64_t last_frame_timestamp_ms_ GUARDED_BY(lock_);
+
+    webrtc::RtpParameters rtp_parameters_;
+    int global_max_bitrate_;

[pthatcher1, 2016/03/16 00:48:42]

We have:

parameters_;
rtp_parameters_;
global_max_bitrate_;

First, I think we can remove the last one, and simply compute the min of the
other two every time we reconfigure the encoder and not store it.

Second, we should make it clear why we have two parameters, and what goes in
each.

Perhaps something like:

// parameters_ contains settings that are the same for all streams in the
MediaChannel, such as codecs and header extensions.
VideoSendStreamParameters parameters_;
// rtp_parameters_ contains settings that are unique for each stream, such as
max bitrate.
// TODO: Move ssrcs_ and ssrcs_groups_ into rtp_parameters_.
// TODO: Combine parameters_ and rtp_parameters once we have only one stream per
MediaChannel.
webrtc::RtpParameters rtp_parameters_;

[skvlad, 2016/03/16 02:29:22]

Done.

   };
 
   // Wrapper for the receiver part, contains configs etc. that are needed to