feat: video publishing (#42)

- Prepare webrtc abstraction ( for future wasm support )
- Added track publish support for videos
  - Added LogoTrack example to simple_room demo
- Lot of cleanup
- There are compiler warnings I'll solve on our v1 release

webrtc-sys/include/livekit/peer_connection.h

@@ -57,7 +57,7 @@ class PeerConnection {
   void set_remote_description(std::unique_ptr<SessionDescription> desc,
                               NativeSetRemoteSdpObserverHandle& observer) const;
 
-  std::unique_ptr<DataChannel> create_data_channel(
+  std::shared_ptr<DataChannel> create_data_channel(
       rust::String label,
       std::unique_ptr<NativeDataChannelInit> init) const;
 
@@ -84,24 +84,34 @@ class PeerConnection {
 
   rust::Vec<RtpTransceiverPtr> get_transceivers() const;
 
+  std::unique_ptr<SessionDescription> current_local_description() const;
+
+  std::unique_ptr<SessionDescription> current_remote_description() const;
+
+  std::unique_ptr<SessionDescription> pending_local_description() const;
+
+  std::unique_ptr<SessionDescription> pending_remote_description() const;
+
   std::unique_ptr<SessionDescription> local_description() const;
 
   std::unique_ptr<SessionDescription> remote_description() const;
 
+  PeerConnectionState connection_state() const;
+
   SignalingState signaling_state() const;
 
   IceGatheringState ice_gathering_state() const;
 
   IceConnectionState ice_connection_state() const;
 
-  void close();
+  void close() const;
 
  private:
   std::shared_ptr<RTCRuntime> rtc_runtime_;
   rtc::scoped_refptr<webrtc::PeerConnectionInterface> peer_connection_;
 };
 
-static std::unique_ptr<PeerConnection> _unique_peer_connection() {
+static std::shared_ptr<PeerConnection> _shared_peer_connection() {
   return nullptr;  // Ignore
 }
 
@@ -126,6 +136,8 @@ class NativePeerConnectionObserver : public webrtc::PeerConnectionObserver {
       std::shared_ptr<RTCRuntime> rtc_runtime,
       rust::Box<PeerConnectionObserverWrapper> observer);
 
+  ~NativePeerConnectionObserver();
+
   void OnSignalingChange(
       webrtc::PeerConnectionInterface::SignalingState new_state) override;
 
@@ -188,7 +200,7 @@ class NativePeerConnectionObserver : public webrtc::PeerConnectionObserver {
   rust::Box<PeerConnectionObserverWrapper> observer_;
 };
 
-std::unique_ptr<NativePeerConnectionObserver>
+std::shared_ptr<NativePeerConnectionObserver>
 create_native_peer_connection_observer(
     std::shared_ptr<RTCRuntime> rtc_runtime,
     rust::Box<PeerConnectionObserverWrapper> observer);