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

sdk/lib/io/common.dart

 // Copyright (c) 2012, 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;
 
 // Constants used when working with native ports.
 // These must match the constants in runtime/bin/dartutils.h class CObject.
 const int _SUCCESS_RESPONSE = 0;
 const int _ILLEGAL_ARGUMENT_RESPONSE = 1;
@@ skipping 72 matching lines @@
       sb..write(": errno = ")
         ..write(errorCode.toString());
     }
     return sb.toString();
   }
 }
 
 
 // Object for holding a buffer and an offset.
 class _BufferAndStart {
-  List<int> buffer;
+  List buffer;
   int start;
   _BufferAndStart(this.buffer, this.start);
 }
 
 // Ensure that the input List can be serialized through a native port.
 // Only Int8List and Uint8List Lists are serialized directly.
 // All other lists are first copied into a Uint8List. This has the added
 // benefit that it is faster to access from the C code as well.
 _BufferAndStart _ensureFastAndSerializableByteData(
-    List<int> buffer, int start, int end) {
+    List buffer, int start, int end) {
   if (buffer is Uint8List || buffer is Int8List) {
     return new _BufferAndStart(buffer, start);
   }
   int length = end - start;
   var newBuffer = new Uint8List(length);
   int j = start;
   for (int i = 0; i < length; i++) {
     int value = buffer[j];
     if (value is! int) {
       throw new ArgumentError("List element is not an integer at index $j");
     }
     newBuffer[i] = value;
     j++;
   }
   return new _BufferAndStart(newBuffer, 0);
 }
 
 
 class _IOCrypto {
   external static Uint8List getRandomBytes(int count);
 }