Fixes NetworkInterface.list crash on Android

sdk/lib/io/socket.dart

Index: sdk/lib/io/socket.dart
diff --git a/sdk/lib/io/socket.dart b/sdk/lib/io/socket.dart
index 4da5bb83e5c6e4ade3301fdc51c69f0b56017275..30e4eb2c2dda9d357bf466b1a8c71499aecb7ab4 100644
--- a/sdk/lib/io/socket.dart
+++ b/sdk/lib/io/socket.dart
@@ -145,8 +145,8 @@ abstract class InternetAddress {
 
 
 /**
- * A [NetworkInterface] represent an active network interface on the current
- * system. It contains a list of [InternetAddress]s, that's bound to the
+ * A [NetworkInterface] represents an active network interface on the current
+ * system. It contains a list of [InternetAddress]es that are bound to the
  * interface.
  */
 abstract class NetworkInterface {
@@ -161,12 +161,19 @@ abstract class NetworkInterface {
   String get index;
 
   /**
-   * Get a list of [InternetAddress]s currently bound to this
+   * Get a list of [InternetAddress]es currently bound to this
    * [NetworkInterface].
    */
   List<InternetAddress> get addresses;
 
   /**
+   * Whether [list] is supported.
+   *
+   * [list] is currently unsupported on Android.
+   */
+  external static bool get listSupported;
+
+  /**
    * Query the system for [NetworkInterface]s.
    *
    * If [includeLoopback] is `true`, the returned list will include the