Use the encoding parameter for writeString on RandomAccessFile objects.

runtime/bin/file_impl.dart

Index: runtime/bin/file_impl.dart
diff --git a/runtime/bin/file_impl.dart b/runtime/bin/file_impl.dart
index 0aa31fb0291a2ec2602b7a9c2b002804d072e117..e3c9e21a5c33d427bd2bedaf61561f4c8508cbeb 100644
--- a/runtime/bin/file_impl.dart
+++ b/runtime/bin/file_impl.dart
@@ -902,32 +902,15 @@ class _RandomAccessFile extends _FileBase implements RandomAccessFile {
 
   Future<RandomAccessFile> writeString(String string,
                                        [Encoding encoding = Encoding.UTF_8]) {
-    _ensureFileService();
-    Completer<RandomAccessFile> completer = new Completer<RandomAccessFile>();
-    if (closed) return _completeWithClosedException(completer);
-    List request = new List(3);
-    request[0] = _WRITE_STRING_REQUEST;

[Søren Gjesse, 2012/10/30 10:24:31]

Shouldn't we fully remove the write string request from the system?

[Mads Ager (google), 2012/10/30 11:34:05]

Whoops! Good catch. Yes we should.

-    request[1] = _id;
-    request[2] = string;
-    return _fileService.call(request).transform((response) {
-      if (_isErrorResponse(response)) {
-        throw _exceptionFromResponse(response,
-                                     "writeString failed for file '$_name'");
-      }
-      return this;
-    });
+    var data = _StringEncoders.encoder(encoding).encodeString(string);
+    return writeList(data, 0, data.length);
   }
 
   static _writeString(int id, String string) native "File_WriteString";
 
   int writeStringSync(String string, [Encoding encoding = Encoding.UTF_8]) {
-    _checkNotClosed();
-    if (string is !String) throw new ArgumentError();
-    var result = _writeString(_id, string);
-    if (result is OSError) {
-      throw new FileIOException("writeString failed for file '$_name'");
-    }
-    return result;
+    var data = _StringEncoders.encoder(encoding).encodeString(string);
+    return writeListSync(data, 0, data.length);
   }
 
   Future<int> position() {