Delete AsyncSocket class, merge into Socket class

Bug: webrtc:13065
Change-Id: I13afee2386ea9c4de0e4fa95133f0c4d3ec826e8
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/227031
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34787}
diff --git a/rtc_base/virtual_socket_server.h b/rtc_base/virtual_socket_server.h
index af86991..dafab54 100644
--- a/rtc_base/virtual_socket_server.h
+++ b/rtc_base/virtual_socket_server.h
@@ -116,7 +116,6 @@
 
   // SocketFactory:
   Socket* CreateSocket(int family, int type) override;
-  AsyncSocket* CreateAsyncSocket(int family, int type) override;
 
   // SocketServer:
   void SetMessageQueue(Thread* queue) override;
@@ -326,7 +325,7 @@
 
 // Implements the socket interface using the virtual network.  Packets are
 // passed as messages using the message queue of the socket server.
-class VirtualSocket : public AsyncSocket,
+class VirtualSocket : public Socket,
                       public MessageHandler,
                       public sigslot::has_slots<> {
  public: