unfork DDC's copy of most SDK libraries

pkg/dev_compiler/tool/input_sdk/lib/core/string_buffer.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.
-
-part of dart.core;
-
-/**
- * A class for concatenating strings efficiently.
- *
- * Allows for the incremental building of a string using write*() methods.
- * The strings are concatenated to a single string only when [toString] is
- * called.
- */
-class StringBuffer implements StringSink {
-
-  /** Creates the string buffer with an initial content. */
-  external StringBuffer([Object content = ""]);
-
-  /**
-   * Returns the length of the content that has been accumulated so far.
-   * This is a constant-time operation.
-   */
-  external int get length;
-
-  /** Returns whether the buffer is empty. This is a constant-time operation. */
-  bool get isEmpty => length == 0;
-
-  /**
-   * Returns whether the buffer is not empty. This is a constant-time
-   * operation.
-   */
-  bool get isNotEmpty => !isEmpty;
-
-  /// Adds the contents of [obj], converted to a string, to the buffer.
-  external void write(Object obj);
-
-  /// Adds the string representation of [charCode] to the buffer.
-  external void writeCharCode(int charCode);
-
-  external void writeAll(Iterable objects, [String separator = ""]);
-
-  external void writeln([Object obj = ""]);
-
-  /**
-   * Clears the string buffer.
-   */
-  external void clear();
-
-  /// Returns the contents of buffer as a concatenated string.
-  external String toString();
-}