Remove abstract from class members in dart libraries

sdk/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 243 matching lines @@
   void backup([int by = 1]) {
     utf32EncodedBytesIterator.backup(4 * by);
   }
 
   int get remaining => (utf32EncodedBytesIterator.remaining + 3) ~/ 4;
 
   void skip([int count = 1]) {
     utf32EncodedBytesIterator.skip(4 * count);
   }
 
-  abstract int decode();
+  int decode();
 }
 
 /**
  * Convert UTF-32BE encoded bytes to codepoints by grouping 4 bytes
  * to produce the unicode codepoint.
  */
 class Utf32beBytesDecoder extends Utf32BytesDecoder {
   Utf32beBytesDecoder(List<int> utf32EncodedBytes, [int offset = 0,
       int length, bool stripBom = true,
       int replacementCodepoint = UNICODE_REPLACEMENT_CHARACTER_CODEPOINT]) :
@@ skipping 35 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);
 }