Introduce (private) ZLibFilter to dart:io.

runtime/bin/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.
 
 // Constants used when working with native ports.
 const int _SUCCESS_RESPONSE = 0;
 const int _ILLEGAL_ARGUMENT_RESPONSE = 1;
 const int _OSERROR_RESPONSE = 2;
 const int _FILE_CLOSED_RESPONSE = 3;
 
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     */
   final String message;
 
   /**
     * Error code supplied by the operating system. Will have the value
     * [noErrorCode] if there is no error code associated with the error.
     */
   final int errorCode;
 }
 
+/**
+ * An [InternalError] can be thrown from native calls when an error occours
+ * inside native code.
+ */
+class InternalError {
+  const InternalError([String this.message = ""]);
+
+  String toString() {
+    if (message.isEmpty) return "InternalError";
+    return "InternalError: $message";
+  }
+
+  final String message;
+}
+
 
 // Check if a List is a builtin VM List type. Returns true
 // if the List is a builtin VM List type and false if it is
 // a user defined List type.
 bool _isBuiltinList(List buffer) native "Common_IsBuiltinList";
 
 
 // Object for holding a buffer and an offset.
 class _BufferAndOffset {
   _BufferAndOffset(List this.buffer, int this.offset);
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   for (int i = 0; i < bytes; i++) {
     int value = buffer[j];
     if (value is! int) {
       throw new FileIOException("List element is not an integer at index $j");
     }
     newBuffer[i] = value;
     j++;
   }
   return new _BufferAndOffset(newBuffer, 0);
 }