Move client/{base, observable, layout, touch, util, view} to samples/ui_lib .

client/util/StringUtils.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.
-
-/**
- * General purpose string manipulation utilities.
- */
-class StringUtils {
-  /**
-   * Returns either [str], or if [str] is null, the value of [defaultStr].
-   */
-  static String defaultString(String str, [String defaultStr='']) {
-    return str === null ? defaultStr : str;
-  }
-
-  /** Parse string to a double, and handle null intelligently */
-  static double parseDouble(String str, [double ifNull = null]) {
-    return (str == null) ? ifNull : Math.parseDouble(str);
-  }
-
-  /** Parse string to a int, and handle null intelligently */
-  static int parseInt(String str, [int ifNull = null]) {
-    return (str == null) ? ifNull : Math.parseInt(str);
-  }
-
-  /** Parse bool to a double, and handle null intelligently */
-  // TODO(jacobr): corelib should have a boolean parsing method
-  static bool parseBool(String str, [bool ifNull = null]) {
-    assert(str == null || str == 'true' || str == 'false');
-    return (str == null) ? ifNull : (str == 'true');
-  }
-}