Fix all strong-mode errors and warnings.

test/web_socket_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 @TestOn('vm')
 
 import 'dart:io';
 
 import 'package:stream_channel/stream_channel.dart';
 import 'package:test/test.dart';
@@ skipping 17 matching lines @@
       var request = await client.openUrl(
           "GET", Uri.parse("http://localhost:${server.port}"));
       request.headers
         ..set("Connection", "Upgrade")
         ..set("Upgrade", "websocket")
         ..set("Sec-WebSocket-Key", "x3JJHMbDL1EzLkh9GBhXDw==")
         ..set("Sec-WebSocket-Version", "13");
 
       var response = await request.close();
       var socket = await response.detachSocket();
-      var innerChannel = new StreamChannel(socket, socket);
+      var innerChannel = new StreamChannel<List<int>>(socket, socket);
       var webSocket = new WebSocketChannel(innerChannel, serverSide: false);
 
       var n = 0;
       await webSocket.stream.listen((message) {
         if (n == 0) {
           expect(message, equals("hello!"));
           webSocket.sink.add("ping");
         } else if (n == 1) {
           expect(message, equals("pong"));
           webSocket.sink.close();
@@ skipping 11 matching lines @@
         var response = request.response;
         response.statusCode = 101;
         response.headers
           ..set("Connection", "Upgrade")
           ..set("Upgrade", "websocket")
           ..set("Sec-WebSocket-Accept", WebSocketChannel
               .signKey(request.headers.value('Sec-WebSocket-Key')));
         response.contentLength = 0;
 
         var socket = await response.detachSocket();
-        var innerChannel = new StreamChannel(socket, socket);
+        var innerChannel = new StreamChannel<List<int>>(socket, socket);
         var webSocket = new WebSocketChannel(innerChannel);
         webSocket.sink.add("hello!");
 
         var message = await webSocket.stream.first;
         expect(message, equals("ping"));
         webSocket.sink.add("pong");
         webSocket.sink.close();
       });
 
       var webSocket = await WebSocket.connect('ws://localhost:${server.port}');
       var n = 0;
       await webSocket.listen((message) {
         if (n == 0) {
           expect(message, equals("hello!"));
           webSocket.add("ping");
         } else if (n == 1) {
           expect(message, equals("pong"));
           webSocket.close();
           server.close();
         } else {
           fail("Only expected two messages.");
         }
         n++;
       }).asFuture();
     });
   });
 }