Make List.from and Iterable.toList default to not growable.

pkg/args/lib/args.dart

 // Copyright (c) 2013, 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.
 
 /**
  * This library lets you define parsers for parsing raw command-line arguments
  * into a set of options and values using [GNU][] and [POSIX][] style options.
  *
  * ## Defining options ##
  *
@@ skipping 289 matching lines @@
     options[name] = new Option(name, abbr, help, allowed, allowedHelp,
         defaultsTo, callback, isFlag: isFlag, negatable: negatable,
         allowMultiple: allowMultiple);
   }
 
   /**
    * Parses [args], a list of command-line arguments, matches them against the
    * flags and options defined by this parser, and returns the result.
    */
   ArgResults parse(List<String> args) =>
-      new Parser(null, this, args.toList(growable: true)).parse();
+      new Parser(null, this, args.toList()).parse();
 
   /**
    * Generates a string displaying usage information for the defined options.
    * This is basically the help text shown on the command line.
    */
   String getUsage() => new Usage(this).generate();
 
   /**
    * Get the default value for an option. Useful after parsing to test
    * if the user specified something other than the default.
@@ skipping 69 matching lines @@
   operator [](String name) {
     if (!_options.containsKey(name)) {
       throw new ArgumentError(
           'Could not find an option named "$name".');
     }
 
     return _options[name];
   }
 
   /** Get the names of the options as a [Collection]. */
-  Collection<String> get options => _options.keys.toList();
+  Collection<String> get options => _options.keys.toList(growable: false);
 }