[dart:io] Adds Platform.operatingSystemVersion

sdk/lib/io/platform.dart

Index: sdk/lib/io/platform.dart
diff --git a/sdk/lib/io/platform.dart b/sdk/lib/io/platform.dart
index 6ec48e36138c3d9ccec1050e8455617c3af7f0a4..01be4ca910285bb9aa82633c87109744d36fa40d 100644
--- a/sdk/lib/io/platform.dart
+++ b/sdk/lib/io/platform.dart
@@ -69,6 +69,7 @@ class Platform {
   static final _numberOfProcessors = _Platform.numberOfProcessors;
   static final _pathSeparator = _Platform.pathSeparator;
   static final _operatingSystem = _Platform.operatingSystem;
+  static final _operatingSystemVersion = _Platform.operatingSystemVersion;
   static final _localHostname = _Platform.localHostname;
   static final _version = _Platform.version;
   static final _localeName = _Platform.localeName;
@@ -94,6 +95,11 @@ class Platform {
    */
   static String get operatingSystem => _operatingSystem;
 
+  /**
+   * A string representing the version of the operating system or platform.
+   */
+  static String get operatingSystemVersion => _operatingSystemVersion;
+
   /**
    * The local hostname for the system.
    */