Remove language directory.

dart/language/grammar/stringbuffer.dart

-// Copyright (c) 2011, 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.
-
-class StringBuffer {
-
-  // Constructor. Optional argument [content] takes initial content.
-  StringBuffer([String content = ""]) {
-    init(content);
-  }
-
-  // Returns the length of the buffer.
-  int get length() {
-    return length_;
-  }
-
-  // Appends item to the buffer.
-  void append(String str) {
-    list_.add(str);
-    length_ += str.length;
-  }
-
-  // Appends all items in strings to the buffer.
-  void appendAll(Collection<String> strings) {
-    strings.forEach((str) { append(str); });
-  }
-
-  // Clears the string buffer.
-  void clear() {
-    list_ = [];
-    length_ = 0;
-  }
-
-  // Sets contents of buffer to str.
-  void init(String str) {
-    if (str.isEmpty()) {
-      clear();
-    } else {
-      list_ = [str];
-      length_ += str.length;
-    }
-  }
-
-  // Returns contents of buffer as a concatenated string.
-  String toString() {
-    String result = String.join(list_, "");
-    list_ = [result];
-    return result;
-  }
-
-  List list_;
-  int length_;
-}