Remove channel ids from various interfaces.

Starts by removing channel/engine id from ViEChannel which propagates
down to the RTP/RTCP module as well as the transport class.

IncomingVideoStream::RenderFrame() is untouched for now but receives a
fake id instead of the previous channel id. Added a TODO to remove it
later but the RenderFrame call is implemented in a lot of
platform-dependent files and should probably remove the "manager" aspect
of renderers, so preferring to do it separately

BUG=webrtc:1695
R=henrika@webrtc.org, mflodman@webrtc.org

Review URL: https://codereview.webrtc.org/1335353005 .

Cr-Commit-Position: refs/heads/master@{#9978}

webrtc/modules/rtp_rtcp/source/rtcp_receiver.h

@@ -29,8 +29,7 @@ class ModuleRtpRtcpImpl;
 class RTCPReceiver : public TMMBRHelp
 {
 public:
- RTCPReceiver(int32_t id,
-              Clock* clock,
+ RTCPReceiver(Clock* clock,
               bool receiver_only,
               RtcpPacketTypeCounterObserver* packet_type_counter_observer,
               RtcpBandwidthObserver* rtcp_bandwidth_observer,