Allow binding the vm service to IPv6 addresses.

runtime/bin/vmservice/server.dart

Index: runtime/bin/vmservice/server.dart
diff --git a/runtime/bin/vmservice/server.dart b/runtime/bin/vmservice/server.dart
index 826205326a4d1390e4f4987fff3738c4683c5dcc..a17c2cfaf2f7b5271525f893ed226bd18a0799b2 100644
--- a/runtime/bin/vmservice/server.dart
+++ b/runtime/bin/vmservice/server.dart
@@ -135,9 +135,10 @@ class Server {
     var ip = _server.address.address;
     var port = _server.port;
     if (useAuthToken) {
-      return Uri.parse('http://$ip:$port/$serviceAuthToken/');
+      return new Uri(scheme: 'http', host: ip, port: port,
+                     path: serviceAuthToken);
     } else {
-      return Uri.parse('http://$ip:$port/');
+      return new Uri(scheme: 'http', host: ip, port: port);
     }
   }
 
@@ -154,6 +155,7 @@ class Server {
     // Explicitly add localhost and 127.0.0.1 on any port (necessary for
     // adb port forwarding).
     if ((uri.host == 'localhost') ||
+        (uri.host == '::1') ||
         (uri.host == '127.0.0.1')) {
       return true;
     }
@@ -300,28 +302,28 @@ class Server {
     }
   }
 
-  Future startup() {
+  Future startup() async {
     if (_server != null) {
       // Already running.
-      return new Future.value(this);
+      return this;
     }
 
-    var address = new InternetAddress(_ip);
     // Startup HTTP server.
-    return HttpServer.bind(address, _port).then((s) {
-      _server = s;
+    try {
+      var address = (await InternetAddress.lookup(_ip))[0];

[rmacnak, 2016/11/18 23:50:33]

On my workstation, the IPv6 result comes back first, and presumably this is a
signal that it is preferred.

[Cutch, 2016/11/19 22:21:37]

This code should stay consistent with the existing behaviour and always choose
ipv4 if it is available and then ipv6.

[rmacnak, 2016/11/22 04:00:52]

Done.

+      _server = await HttpServer.bind(address, _port);
       _server.listen(_requestHandler, cancelOnError: true);
       print('Observatory listening on $serverAddress');
       // Server is up and running.
       _notifyServerState(serverAddress.toString());
       onServerAddressChange('$serverAddress');
       return this;
-    }).catchError((e, st) {
+    } catch (e, st) {
       print('Could not start Observatory HTTP server:\n$e\n$st\n');
       _notifyServerState("");
       onServerAddressChange(null);
       return this;
-    });
+    }
   }
 
   Future cleanup(bool force) {