Fixing Location.origin to work on non-WebKit browsers.

tests/html/location_test.dart

 library LocationTest;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:html';
+import 'dart:uri';
 
 main() {
   useHtmlConfiguration();
 
   var isLocation = predicate((x) => x is Location, 'is a Location');
 
   test('location hash', () {
       final location = window.location;
       expect(location, isLocation);
 
       // The only navigation we dare try is hash.
       location.hash = 'hello';
       var h = location.hash;
       expect(h, '#hello');
     });
+
+  test('location.origin', () {
+    var origin = window.location.origin;
+
+    // We build up the origin from Uri, then make sure that it matches.
+    var uri = new Uri(window.location.href);
+    var reconstructedOrigin = '${uri.scheme}://${uri.domain}';
+    if (uri.port != 0) {
+      reconstructedOrigin = '$reconstructedOrigin:${uri.port}';
+    }
+
+    expect(origin, reconstructedOrigin);
+  });
 }