Enable setting the maximum bitrate limit in RtpSender.

webrtc/media/base/mediachannel.h

Index: webrtc/media/base/mediachannel.h
diff --git a/webrtc/media/base/mediachannel.h b/webrtc/media/base/mediachannel.h
index badec464cdbbb847a3eb624c1831ffa775a7488a..7414e9af7003abba19b27be30f5551b68286d4bf 100644
--- a/webrtc/media/base/mediachannel.h
+++ b/webrtc/media/base/mediachannel.h
@@ -15,6 +15,7 @@
 #include <string>
 #include <vector>
 
+#include "webrtc/api/rtpparameters.h"
 #include "webrtc/base/basictypes.h"
 #include "webrtc/base/buffer.h"
 #include "webrtc/base/dscp.h"
@@ -79,6 +80,15 @@ static std::string VectorToString(const std::vector<T>& vals) {
     return ost.str();
 }
 
+template <typename T>
+static T MinPositive(T a, T b) {

[pthatcher1, 2016/03/12 01:21:03]

This would be more clear as the min of rtc::Optionals. 

[skvlad, 2016/03/15 21:18:18]

I'm going to send a separate code review for the change to replace the magic
constants (such as -1) with rtc::Optional in bitrate limiting code everywhere.
Until then, can we keep it like this?

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

sure

+  if (a <= 0)

[Taylor Brandstetter, 2016/03/12 01:57:06]

nit: {}s

[skvlad, 2016/03/15 21:18:18]

Done.

+    return b;
+  if (b <= 0)
+    return a;
+  return std::min(a, b);
+}
+
 // Construction-time settings, passed to
 // MediaControllerInterface::Create, and passed on when creating
 // MediaChannels.
@@ -892,6 +902,9 @@ class VoiceMediaChannel : public MediaChannel {
   virtual ~VoiceMediaChannel() {}
   virtual bool SetSendParameters(const AudioSendParameters& params) = 0;
   virtual bool SetRecvParameters(const AudioRecvParameters& params) = 0;
+  virtual webrtc::RTCRtpParameters GetRtpParameters(uint32_t ssrc) = 0;

[Taylor Brandstetter, 2016/03/12 01:57:06]

Again, can probably be const.

[skvlad, 2016/03/15 21:18:18]

Done.

+  virtual bool SetRtpParameters(uint32_t ssrc,
+                                const webrtc::RTCRtpParameters& parameters) = 0;
   // Starts or stops playout of received audio.
   virtual bool SetPlayout(bool playout) = 0;
   // Starts or stops sending (and potentially capture) of local audio.
@@ -964,6 +977,9 @@ class VideoMediaChannel : public MediaChannel {
 
   virtual bool SetSendParameters(const VideoSendParameters& params) = 0;
   virtual bool SetRecvParameters(const VideoRecvParameters& params) = 0;
+  virtual webrtc::RTCRtpParameters GetRtpParameters(uint32_t ssrc) = 0;
+  virtual bool SetRtpParameters(uint32_t ssrc,
+                                const webrtc::RTCRtpParameters& parameters) = 0;
   // Gets the currently set codecs/payload types to be used for outgoing media.
   virtual bool GetSendCodec(VideoCodec* send_codec) = 0;
   // Starts or stops transmission (and potentially capture) of local video.