Implement fromEnvironment on bool, int and String

runtime/lib/string_patch.dart

 // Copyright (c) 2012, 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.
 
 patch class String {
   /* patch */ factory String.fromCharCodes(Iterable<int> charCodes) {
     return _StringBase.createFromCharCodes(charCodes);
   }
+
+  /* patch */ const factory String.fromEnvironment(String name,
+                                                   {String defaultValue})
+      native "String_fromEnvironment";
 }
 
 
 /**
  * [_StringBase] contains common methods used by concrete String
  * implementations, e.g., _OneByteString.
  */
 class _StringBase {
 
   factory _StringBase._uninstantiable() {
@@ skipping 667 matching lines @@
 class _CodeUnits extends Object with ListMixin<int>,
                                      UnmodifiableListMixin<int> {
   /** The string that this is the code units of. */
   String _string;
 
   _CodeUnits(this._string);
 
   int get length => _string.length;
   int operator[](int i) => _string.codeUnitAt(i);
 }