Add a WebSocketChannel class.

lib/src/web_socket/deprecated.dart

Index: lib/src/web_socket/deprecated.dart
diff --git a/lib/src/web_socket.dart b/lib/src/web_socket/deprecated.dart
similarity index 81%
copy from lib/src/web_socket.dart
copy to lib/src/web_socket/deprecated.dart
index a11840c09f523322c9b0f3095ddea6ee98c7a102..c2162d7be9955b59f02a04fa66e686e012b1918f 100644
--- a/lib/src/web_socket.dart
+++ b/lib/src/web_socket/deprecated.dart
@@ -6,17 +6,11 @@ import 'dart:async';
 
 import 'package:crypto/crypto.dart';
 
-import 'copy/web_socket_impl.dart';
+import '../copy/web_socket_impl.dart';
+import 'channel.dart';
 
-/// An implementation of the WebSocket protocol that's not specific to "dart:io"
-/// or to any particular HTTP API.
-///
-/// Because this is HTTP-API-agnostic, it doesn't handle the initial [WebSocket
-/// handshake][]. This needs to be handled manually by the user of the code.
-/// Once that's been done, [new CompatibleWebSocket] can be called with the
-/// underlying socket and it will handle the remainder of the protocol.
-///
-/// [WebSocket handshake]: https://tools.ietf.org/html/rfc6455#section-4
+/// Use [WebSocketChannel] instead.
+@Deprecated("Will be removed in 3.0.0.")
 abstract class CompatibleWebSocket implements Stream, StreamSink {
   /// The interval for sending ping signals.
   ///
@@ -99,14 +93,3 @@ abstract class CompatibleWebSocket implements Stream, StreamSink {
   /// [reason]: https://tools.ietf.org/html/rfc6455#section-7.1.6
   Future close([int closeCode, String closeReason]);
 }
-
-/// An exception thrown by [CompatibleWebSocket].
-class CompatibleWebSocketException implements Exception {
-  final String message;
-
-  CompatibleWebSocketException([this.message]);
-
-  String toString() => message == null
-      ? "CompatibleWebSocketException" :
-        "CompatibleWebSocketException: $message";
-}