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/proxy_unittest.cc b/rtc_base/proxy_unittest.cc
index d73d9de..9e3898e 100644
--- a/rtc_base/proxy_unittest.cc
+++ b/rtc_base/proxy_unittest.cc
@@ -43,8 +43,8 @@
 
 // Tests whether we can use a SOCKS5 proxy to connect to a server.
 TEST_F(ProxyTest, TestSocks5Connect) {
-  rtc::AsyncSocket* socket =
-      ss()->CreateAsyncSocket(kSocksProxyIntAddr.family(), SOCK_STREAM);
+  rtc::Socket* socket =
+      ss()->CreateSocket(kSocksProxyIntAddr.family(), SOCK_STREAM);
   rtc::AsyncSocksProxySocket* proxy_socket = new rtc::AsyncSocksProxySocket(
       socket, kSocksProxyIntAddr, "", rtc::CryptString());
   // TODO: IPv6-ize these tests when proxy supports IPv6.