Fix typos in base64.dart

sdk/lib/convert/base64.dart

 // Copyright (c) 2015, 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.
 
 part of dart.convert;
 
 /**
  * An instance of [Base64Codec].
  *
  * This instance provides a convenient access to
@@ skipping 47 matching lines @@
 
   String convert(List<int> input) {
     if (input.isEmpty) return "";
     var encoder = new _Base64Encoder();
     Uint8List buffer = encoder.encode(input, 0, input.length, true);
     return new String.fromCharCodes(buffer);
   }
 
   ByteConversionSink startChunkedConversion(Sink<String> sink) {
     if (sink is StringConversionSink) {
-      return new _Utf8Base64EncoderSink(sink.asUtf8Sink());
+      return new _Utf8Base64EncoderSink(sink.asUtf8Sink(false));
     }
     return new _AsciiBase64EncoderSink(sink);
   }
 
   Stream<String> bind(Stream<List<int>> stream) {
     return new Stream<String>.eventTransformed(
         stream,
         (EventSink sink) =>
             new _ConverterStreamEventSink<List<int>, String>(this, sink));
   }
@@ skipping 489 matching lines @@
    * That means zero or one padding character (depending on [_state])
    * and nothing else.
    */
   static int _checkPadding(String input, int start, int end, int state) {
     assert(_hasSeenPadding(state));
     if (start == end) return state;
     int expectedPadding = _statePadding(state);
     if (expectedPadding > 0) {
       int firstChar = input.codeUnitAt(start);
       if (firstChar != _paddingChar) {
-        throw new FormatException("Missing padding character", string, start);
+        throw new FormatException("Missing padding character", input, start);
       }
       state = _encodePaddingState(0);
       start++;
     }
     if (start != end) {
       throw new FormatException("Invalid character after padding",
                                 input, start);
     }
     return state;
   }
@@ skipping 21 matching lines @@
     end = RangeError.checkValidRange(start, end, string.length);
     if (start == end) return;
     Uint8List buffer = _decoder.decode(string, start, end);
     if (buffer != null) _sink.add(buffer);
     if (isLast) {
       _decoder.close(string, end);
       _sink.close();
     }
   }
 }