- Change "static final" to "static const" in the lib/ directory.

lib/utf/utf_core.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.
 
 /**
  * Provide a list of Unicode codepoints for a given string.
  */
 List<int> stringToCodepoints(String str) {
   List<int> codepoints;
   // TODO _is16BitCodeUnit() is used to work around a bug with dart2js
@@ skipping 34 matching lines @@
   if (_test16BitCodeUnit == null) {
     _test16BitCodeUnit = (new String.fromCharCodes([0x1D11E])) ==
         (new String.fromCharCodes([0xD11E]));
   }
   return _test16BitCodeUnit;
 }
 
 /**
  * Invalid codepoints or encodings may be substituted with the value U+fffd.
  */
-final int UNICODE_REPLACEMENT_CHARACTER_CODEPOINT = 0xfffd;
-final int UNICODE_BOM = 0xfeff;
-final int UNICODE_UTF_BOM_LO = 0xff;
-final int UNICODE_UTF_BOM_HI = 0xfe;
+const int UNICODE_REPLACEMENT_CHARACTER_CODEPOINT = 0xfffd;
+const int UNICODE_BOM = 0xfeff;
+const int UNICODE_UTF_BOM_LO = 0xff;
+const int UNICODE_UTF_BOM_HI = 0xfe;
 
-final int UNICODE_BYTE_ZERO_MASK = 0xff;
-final int UNICODE_BYTE_ONE_MASK = 0xff00;
-final int UNICODE_VALID_RANGE_MAX = 0x10ffff;
-final int UNICODE_PLANE_ONE_MAX = 0xffff;
-final int UNICODE_UTF16_RESERVED_LO = 0xd800;
-final int UNICODE_UTF16_RESERVED_HI = 0xdfff;
-final int UNICODE_UTF16_OFFSET = 0x10000;
-final int UNICODE_UTF16_SURROGATE_UNIT_0_BASE = 0xd800;
-final int UNICODE_UTF16_SURROGATE_UNIT_1_BASE = 0xdc00;
-final int UNICODE_UTF16_HI_MASK = 0xffc00;
-final int UNICODE_UTF16_LO_MASK = 0x3ff;
+const int UNICODE_BYTE_ZERO_MASK = 0xff;
+const int UNICODE_BYTE_ONE_MASK = 0xff00;
+const int UNICODE_VALID_RANGE_MAX = 0x10ffff;
+const int UNICODE_PLANE_ONE_MAX = 0xffff;
+const int UNICODE_UTF16_RESERVED_LO = 0xd800;
+const int UNICODE_UTF16_RESERVED_HI = 0xdfff;
+const int UNICODE_UTF16_OFFSET = 0x10000;
+const int UNICODE_UTF16_SURROGATE_UNIT_0_BASE = 0xd800;
+const int UNICODE_UTF16_SURROGATE_UNIT_1_BASE = 0xdc00;
+const int UNICODE_UTF16_HI_MASK = 0xffc00;
+const int UNICODE_UTF16_LO_MASK = 0x3ff;
 
 /**
  * Encode code points as UTF16 code units.
  */
 List<int> _codepointsToUtf16CodeUnits(
     List<int> codepoints, [int offset = 0, int length,
     int replacementCodepoint = UNICODE_REPLACEMENT_CHARACTER_CODEPOINT]) {
 
   _ListRange listRange = new _ListRange(codepoints, offset, length);
   int encodedLength = 0;
@@ skipping 185 matching lines @@
     _offset -= by;
   }
 
   int get remaining() => _end - _offset;
 
   void skip([int count = 1]) {
     _offset += count;
   }
 }