Revert "Fix remaining strong-mode warnings and errors in dart:io."

sdk/lib/io/stdio.dart

 // Copyright (c) 2013, 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.
 
 part of dart.io;
 
 const int _STDIO_HANDLE_TYPE_TERMINAL = 0;
 const int _STDIO_HANDLE_TYPE_PIPE = 1;
 const int _STDIO_HANDLE_TYPE_FILE = 2;
 const int _STDIO_HANDLE_TYPE_SOCKET = 3;
@@ skipping 39 matching lines @@
    * terminator. Default is `false`.
    *
    * If end-of-file is reached after any bytes have been read from stdin,
    * that data is returned.
    * Returns `null` if no bytes preceeded the end of input.
    */
   String readLineSync({Encoding encoding: SYSTEM_ENCODING,
                        bool retainNewlines: false}) {
     const CR = 13;
     const LF = 10;
-    final List<int> line = <int>[];
+    final List line = [];
     // On Windows, if lineMode is disabled, only CR is received.
     bool crIsNewline = Platform.isWindows &&
         (stdioType(stdin) == StdioType.TERMINAL) &&
         !lineMode;
     if (retainNewlines) {
       int byte;
       do {
         byte = readByteSync();
         if (byte < 0) {
           break;
@@ skipping 281 matching lines @@
 }
 
 
 class _StdIOUtils {
   external static _getStdioOutputStream(int fd);
   external static Stdin _getStdioInputStream();
   /// Returns the socket type or `null` if [socket] is not a builtin socket.
   external static int _socketType(Socket socket);
   external static _getStdioHandleType(int fd);
 }