Some cleanup in BaseChannel RTCP mux code.

webrtc/pc/channel.h

Index: webrtc/pc/channel.h
diff --git a/webrtc/pc/channel.h b/webrtc/pc/channel.h
index 3c00ee3d4a1b684a826cc63c960f22d78c63171b..eea1d7f0da0508ced02ff24d3c01ef3171bd25e0 100644
--- a/webrtc/pc/channel.h
+++ b/webrtc/pc/channel.h
@@ -70,6 +70,7 @@ class BaseChannel
       public MediaChannel::NetworkInterface,
       public ConnectionStatsGetter {
  public:
+  // |rtcp| represents whether or not this channel uses RTCP.
   BaseChannel(rtc::Thread* worker_thread,
               rtc::Thread* network_thread,
               MediaChannel* channel,
@@ -197,7 +198,6 @@ class BaseChannel
   rtc::Thread* signaling_thread() {
     return transport_controller_->signaling_thread();
   }
-  bool rtcp_transport_enabled() const { return rtcp_transport_enabled_; }
 
   void ConnectToTransportChannel(TransportChannel* tc);
   void DisconnectFromTransportChannel(TransportChannel* tc);
@@ -342,34 +342,37 @@ class BaseChannel
   // Transport related members that should be accessed from network thread.
   TransportController* const transport_controller_;
   std::string transport_name_;
-  bool rtcp_transport_enabled_;
-  TransportChannel* transport_channel_;
+  // Is RTCP used at all by this type of channel?
+  // Expected to be true (as of typing this) for everything except data
+  // channels.
+  const bool rtcp_enabled_;
+  TransportChannel* transport_channel_ = nullptr;
   std::vector<std::pair<rtc::Socket::Option, int> > socket_options_;
-  TransportChannel* rtcp_transport_channel_;
+  TransportChannel* rtcp_transport_channel_ = nullptr;
   std::vector<std::pair<rtc::Socket::Option, int> > rtcp_socket_options_;
   SrtpFilter srtp_filter_;
   RtcpMuxFilter rtcp_mux_filter_;
   BundleFilter bundle_filter_;
-  bool rtp_ready_to_send_;
-  bool rtcp_ready_to_send_;
-  bool writable_;
-  bool was_ever_writable_;
-  bool has_received_packet_;
-  bool dtls_keyed_;
-  bool secure_required_;
+  bool rtp_ready_to_send_ = false;
+  bool rtcp_ready_to_send_ = false;
+  bool writable_ = false;
+  bool was_ever_writable_ = false;
+  bool has_received_packet_ = false;
+  bool dtls_keyed_ = false;
+  bool secure_required_ = false;
   rtc::CryptoOptions crypto_options_;
-  int rtp_abs_sendtime_extn_id_;
+  int rtp_abs_sendtime_extn_id_ = -1;
 
   // MediaChannel related members that should be access from worker thread.
   MediaChannel* const media_channel_;
   // Currently enabled_ flag accessed from signaling thread too, but it can
   // be changed only when signaling thread does sunchronious call to worker
   // thread, so it should be safe.
-  bool enabled_;
+  bool enabled_ = false;
   std::vector<StreamParams> local_streams_;
   std::vector<StreamParams> remote_streams_;
-  MediaContentDirection local_content_direction_;
-  MediaContentDirection remote_content_direction_;
+  MediaContentDirection local_content_direction_ = MD_INACTIVE;
+  MediaContentDirection remote_content_direction_ = MD_INACTIVE;
 };
 
 // VoiceChannel is a specialization that adds support for early media, DTMF,