Unify most of our utf8 implementations. This takes the implementation

lib/utf/utf16.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.
 
-#library("utf16");
-#import("unicode_core.dart");
-#import("unicode.dart");
 
 /**
  * Decodes the UTF-16 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 [replacementCodepoint] to null to throw an IllegalArgumentException
  * rather than replace the bad value. The default value for
  * [replacementCodepoint] is U+FFFD.
  */
 IterableUtf16Decoder decodeUtf16AsIterable(List<int> bytes, [int offset = 0,
@@ skipping 195 matching lines @@
 
 /**
  * Return type of [decodeUtf16AsIterable] 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 IterableUtf16Decoder implements Iterable<int> {
   final Function codeunitsProvider;
   final int replacementCodepoint;
 
-  IterableUtf16Decoder._(ListRangeIterator<int> this.codeunitsProvider(),
+  IterableUtf16Decoder._(_ListRangeIterator<int> this.codeunitsProvider(),
       int this.replacementCodepoint);
 
   Utf16CodeUnitDecoder iterator() =>
       new Utf16CodeUnitDecoder.fromListRangeIterator(codeunitsProvider(),
           replacementCodepoint);
 }
 
 /**
  * Convert UTF-16 encoded bytes to UTF-16 code units by grouping 1-2 bytes
  * to produce the code unit (0-(2^16)-1). Relies on BOM to determine
  * endian-ness, and defaults to BE.
  */
-class Utf16BytesToCodeUnitsDecoder implements ListRangeIterator<int> {
-  final ListRangeIterator<int> utf16EncodedBytesIterator;
+class Utf16BytesToCodeUnitsDecoder implements _ListRangeIterator<int> {
+  final _ListRangeIterator<int> utf16EncodedBytesIterator;
   final int replacementCodepoint;
 
   Utf16BytesToCodeUnitsDecoder._fromListRangeIterator(
-      ListRangeIterator<int> this.utf16EncodedBytesIterator,
+      _ListRangeIterator<int> this.utf16EncodedBytesIterator,
       int this.replacementCodepoint);
 
   factory Utf16BytesToCodeUnitsDecoder(List<int> utf16EncodedBytes, [
       int offset = 0, int length,
       int replacementCodepoint = UNICODE_REPLACEMENT_CHARACTER_CODEPOINT]) {
     if (length == null) {
       length = utf16EncodedBytes.length - offset;
     }
     if (hasUtf16beBom(utf16EncodedBytes, offset, length)) {
       return new Utf16beBytesToCodeUnitsDecoder(utf16EncodedBytes, offset + 2,
@@ skipping 59 matching lines @@
 }
 
 /**
  * Convert UTF-16BE encoded bytes to utf16 code units by grouping 1-2 bytes
  * to produce the code unit (0-(2^16)-1).
  */
 class Utf16beBytesToCodeUnitsDecoder extends Utf16BytesToCodeUnitsDecoder {
   Utf16beBytesToCodeUnitsDecoder(List<int> utf16EncodedBytes, [
       int offset = 0, int length, bool stripBom = true,
       int replacementCodepoint = UNICODE_REPLACEMENT_CHARACTER_CODEPOINT]) :
-      super._fromListRangeIterator((new ListRange(utf16EncodedBytes, offset,
+      super._fromListRangeIterator((new _ListRange(utf16EncodedBytes, offset,
       length)).iterator(), replacementCodepoint) {
     if (stripBom && hasUtf16beBom(utf16EncodedBytes, offset, length)) {
       skip();
     }
   }
 
   int decode() {
     int hi = utf16EncodedBytesIterator.next();
     int lo = utf16EncodedBytesIterator.next();
     return (hi << 8) + lo;
   }
 }
 
 /**
  * Convert UTF-16LE encoded bytes to utf16 code units by grouping 1-2 bytes
  * to produce the code unit (0-(2^16)-1).
  */
 class Utf16leBytesToCodeUnitsDecoder extends Utf16BytesToCodeUnitsDecoder {
   Utf16leBytesToCodeUnitsDecoder(List<int> utf16EncodedBytes, [
       int offset = 0, int length, bool stripBom = true,
       int replacementCodepoint = UNICODE_REPLACEMENT_CHARACTER_CODEPOINT]) :
-      super._fromListRangeIterator((new ListRange(utf16EncodedBytes, offset,
+      super._fromListRangeIterator((new _ListRange(utf16EncodedBytes, offset,
       length)).iterator(), replacementCodepoint) {
     if (stripBom && hasUtf16leBom(utf16EncodedBytes, offset, length)) {
       skip();
     }
   }
 
   int decode() {
     int lo = utf16EncodedBytesIterator.next();
     int hi = utf16EncodedBytesIterator.next();
     return (hi << 8) + lo;
   }
 }