Remove dart:codec and move classes into dart:convert.

tests/lib/codec/codec1_test.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.
-
-import 'dart:codec';
-import 'dart:convert';
-
-import 'package:expect/expect.dart';
-
-class MyCodec extends Codec<int, String> {
-  const MyCodec();
-
-  Converter<int, String> get encoder => new IntStringConverter();
-  Converter<String, int> get decoder => new StringIntConverter();
-}
-
-class IntStringConverter extends Converter<int, String> {
-  String convert(int i) => i.toString();
-}
-
-class StringIntConverter extends Converter<String, int> {
-  int convert(String str) => int.parse(str);
-}
-
-class MyCodec2 extends Codec<int, String> {
-  const MyCodec2();
-
-  Converter<int, String> get encoder => new IntStringConverter2();
-  Converter<String, int> get decoder => new StringIntConverter2();
-}
-
-class IntStringConverter2 extends Converter<int, String> {
-  String convert(int i) => (i + 99).toString();
-}
-
-class StringIntConverter2 extends Converter<String, int> {
-  int convert(String str) => int.parse(str) + 400;
-}
-
-const TEST_CODEC = const MyCodec();
-const TEST_CODEC2 = const MyCodec2();
-
-main() {
-  Expect.equals("0", TEST_CODEC.encode(0));
-  Expect.equals(5, TEST_CODEC.decode("5"));
-  Expect.equals(3, TEST_CODEC.decode(TEST_CODEC.encode(3)));
-
-  Expect.equals("99", TEST_CODEC2.encode(0));
-  Expect.equals(405, TEST_CODEC2.decode("5"));
-  Expect.equals(499, TEST_CODEC2.decode(TEST_CODEC2.encode(0)));
-
-  var inverted, fused;
-  inverted = TEST_CODEC.inverted;
-  fused = TEST_CODEC.fuse(inverted);
-  Expect.equals(499, fused.encode(499));
-  Expect.equals(499, fused.decode(499));
-
-  fused = inverted.fuse(TEST_CODEC);
-  Expect.equals("499", fused.encode("499"));
-  Expect.equals("499", fused.decode("499"));
-
-  inverted = TEST_CODEC2.inverted;
-  fused = TEST_CODEC2.fuse(inverted);
-  Expect.equals(499, fused.encode(0));
-  Expect.equals(499, fused.decode(0));
-
-  fused = TEST_CODEC.fuse(inverted);
-  Expect.equals(405, fused.encode(5));
-  Expect.equals(101, fused.decode(2));
-}