Add on_os and on_platform fields.

lib/src/backend/operating_system.dart

 // Copyright (c) 2015, 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.
 
 /// An enum of all operating systems supported by Dart.
 ///
 /// This is used for selecting which operating systems a test can run on. Even
 /// for browser tests, this indicates the operating system of the machine
 /// running the test runner.
 class OperatingSystem {
@@ skipping 24 matching lines @@
   /// system is used. It can't be referenced by name in platform selectors.
   static const none = const OperatingSystem._("none", "none");
 
   /// A list of all instances of [OperatingSystem] other than [none].
   static const all = const [windows, macOS, linux, android, iOS];
 
   /// Finds an operating system by its name.
   ///
   /// If no operating system is found, returns [none].
   static OperatingSystem find(String name) =>
-      all.firstWhere((platform) => platform.name == name, orElse: () => null);
+      all.firstWhere((platform) => platform.identifier == name,

[kevmoo, 2016/02/26 23:06:20]

Rebase oops here – maybe?

+      orElse: () => null);
 
   /// Finds an operating system by the return value from `dart:io`'s
   /// `Platform.operatingSystem`.
   ///
   /// If no operating system is found, returns [none].
   static OperatingSystem findByIoName(String name) {
     switch (name) {
       case "windows": return windows;
       case "macos": return macOS;
       case "linux": return linux;
       case "android": return android;
       case "ios": return iOS;
       default: return none;
     }
   }
 
   /// The human-friendly of the operating system.
   final String name;
 
   /// The identifier used to look up the operating system.
   final String identifier;
 
   /// Whether this is a POSIX-ish operating system.
   bool get isPosix => this != windows && this != none;
 
   const OperatingSystem._(this.name, this.identifier);
 
   String toString() => name;
 }