Placed the protobuf structures in the namespace webrtc::rtclog. Removed the message field from the DebugEvent structure, since it was not used. Added an interface to set config information for VideoReceiveStream and VideoSendStream in the event log. Added function to log full RTCP packets and changed RTP-logging to only log headers. Significantly extended the unit tests for RtcEventLog. R=ivoc@webrtc.org, minyue@webrtc.org, pbos@webrtc.org, stefan@webrtc.org Review URL: https://codereview.webrtc.org/1230973005 . Cr-Commit-Position: refs/heads/master@{#9656}