Added origin property to Uri class Added unit test coverage for origin property

tests/utils/uri_test.dart

Index: tests/utils/uri_test.dart
diff --git a/tests/utils/uri_test.dart b/tests/utils/uri_test.dart
index ff03d4a35e19747844392b33c32dec047d68db15..91451a2bde4f964c1dc07ef99f5cd9d8488fd219 100644
--- a/tests/utils/uri_test.dart
+++ b/tests/utils/uri_test.dart
@@ -106,6 +106,29 @@ main() {
   Expect.stringEquals("http://a/b/g;p/h;s",
                       base.resolve("../g;p/h;s").toString());
 
+  Expect.stringEquals(
+      "http://example.com", 
+      new Uri.fromString("http://example.com/a/b/c").origin);
+  Expect.stringEquals(
+      "https://example.com", 
+      new Uri.fromString("https://example.com/a/b/c").origin);
+  Expect.stringEquals(
+      "http://example.com:1234", 
+      new Uri.fromString("http://example.com:1234/a/b/c").origin);
+  Expect.stringEquals(
+      "https://example.com:1234", 
+      new Uri.fromString("https://example.com:1234/a/b/c").origin);
+  Expect.stringEquals("http:", const Uri("http", null, null).origin);
+  Expect.stringEquals("http://:80", const Uri("http", null, null, 80).origin);
+
+  var expectedException = null;
+  try {
+    var s = const Uri("file://").origin;
+  } catch (IllegalArgumentException e) {
+    expectedException = e;
+  }
+  Expect.isNotNull(expectedException, "origin for non-http/https should fail");
+
   // URI encode tests
   // Note: dart2js won't handle '\ud800\udc00' and frog
   // won't handle '\u{10000}'. So we cons this up synthetically...