Remove spurious types from constructor args that use "this."

lib/utf/utf32.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.
 
 /**
  * Decodes the UTF-32 bytes as an iterable. Thus, the consumer can only convert
  * as much of the input as needed. Determines the byte order from the BOM,
  * or uses big-endian as a default. This method always strips a leading BOM.
  * Set the replacementCharacter to null to throw an ArgumentError
  * rather than replace the bad value.
@@ skipping 155 matching lines @@
  * little-endian byte-order marker (BOM).
  */
 bool hasUtf32leBom(List<int> utf32EncodedBytes, [int offset = 0, int length]) {
   int end = length != null ? offset + length : utf32EncodedBytes.length;
   return (offset + 4) <= end &&
       utf32EncodedBytes[offset] == UNICODE_UTF_BOM_LO &&
       utf32EncodedBytes[offset + 1] == UNICODE_UTF_BOM_HI &&
       utf32EncodedBytes[offset + 2] == 0 && utf32EncodedBytes[offset + 3] == 0;
 }
 
+typedef Utf32BytesDecoder Utf32BytesDecoderProvider();
+
 /**
  * Return type of [decodeUtf32AsIterable] and variants. The Iterable type
  * provides an iterator on demand and the iterator will only translate bytes
  * as requested by the user of the iterator. (Note: results are not cached.)
  */
 class IterableUtf32Decoder implements Iterable<int> {
-  final Function codeunitsProvider;
+  final Utf32BytesDecoderProvider codeunitsProvider;
 
-  IterableUtf32Decoder._(Function this.codeunitsProvider);
+  IterableUtf32Decoder._(this.codeunitsProvider);
 
   Utf32BytesDecoder iterator() => codeunitsProvider();
 }
 
 /**
  * Abstrace parent class converts encoded bytes to codepoints.
  */
 class Utf32BytesDecoder implements _ListRangeIterator {
   final _ListRangeIterator utf32EncodedBytesIterator;
   final int replacementCodepoint;
 
   Utf32BytesDecoder._fromListRangeIterator(
-      _ListRangeIterator this.utf32EncodedBytesIterator,
-      int this.replacementCodepoint);
+      this.utf32EncodedBytesIterator, this.replacementCodepoint);
 
   factory Utf32BytesDecoder(List<int> utf32EncodedBytes, [
       int offset = 0, int length,
       int replacementCodepoint = UNICODE_REPLACEMENT_CHARACTER_CODEPOINT]) {
     if (length == null) {
       length = utf32EncodedBytes.length - offset;
     }
     if (hasUtf32beBom(utf32EncodedBytes, offset, length)) {
       return new Utf32beBytesDecoder(utf32EncodedBytes, offset + 4, length - 4,
           false, replacementCodepoint);
@@ skipping 100 matching lines @@
     value += (utf32EncodedBytesIterator.next() << 24);
     return value;
   }
 }
 
 bool _validCodepoint(int codepoint) {
   return (codepoint >= 0 && codepoint < UNICODE_UTF16_RESERVED_LO) ||
       (codepoint > UNICODE_UTF16_RESERVED_HI &&
       codepoint < UNICODE_VALID_RANGE_MAX);
 }