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/data_channel.h

@@ -37,7 +37,7 @@ class DataChannel {
       std::shared_ptr<RTCRuntime> rtc_runtime,
       rtc::scoped_refptr<webrtc::DataChannelInterface> data_channel);
 
-  void register_observer(NativeDataChannelObserver& observer) const;
+  void register_observer(NativeDataChannelObserver* observer) const;
   void unregister_observer() const;
   bool send(const DataBuffer& buffer) const;
   rust::String label() const;
@@ -52,14 +52,17 @@ class DataChannel {
 std::unique_ptr<NativeDataChannelInit> create_data_channel_init(
     DataChannelInit init);
 
-static std::unique_ptr<DataChannel> _unique_data_channel() {
+static std::shared_ptr<DataChannel> _shared_data_channel() {
   return nullptr;  // Ignore
 }
 
 class NativeDataChannelObserver : public webrtc::DataChannelObserver {
  public:
   explicit NativeDataChannelObserver(
-      rust::Box<DataChannelObserverWrapper> observer);
+      rust::Box<DataChannelObserverWrapper> observer,
+      DataChannel* dc);
+
+  ~NativeDataChannelObserver();
 
   void OnStateChange() override;
   void OnMessage(const webrtc::DataBuffer& buffer) override;
@@ -67,8 +70,10 @@ class NativeDataChannelObserver : public webrtc::DataChannelObserver {
 
  private:
   rust::Box<DataChannelObserverWrapper> observer_;
+  DataChannel* dc_;
 };
 
-std::unique_ptr<NativeDataChannelObserver> create_native_data_channel_observer(
-    rust::Box<DataChannelObserverWrapper> observer);
+std::shared_ptr<NativeDataChannelObserver> create_native_data_channel_observer(
+    rust::Box<DataChannelObserverWrapper> observer,
+    DataChannel* dc);
 }  // namespace livekit