WebRTC代码结构:
http://blog.sina.com.cn/s/blog_40d608bb01010n73.html
http://www.cnblogs.com/fangkm/p/4370492.html
http://mojiapp.cn/a/yuanmashili/2015/0708/542.html
http://max.book118.com/html/2015/1228/32140782.shtm
https://www.slideshare.net/libfetion/webrtc
https://chromium.googlesource.com/external/webrtc/+/master
https://source.codeaurora.org/quic/lc/external/webrtc/tree/webrtc?h=chromium.org/master