First stab at parsing redirecting constructors.

tests/compiler/dart2js/unparser_test.dart

Index: tests/compiler/dart2js/unparser_test.dart
diff --git a/tests/compiler/dart2js/unparser_test.dart b/tests/compiler/dart2js/unparser_test.dart
index 03ac58e0adb42deffefb849a0846063e6c857e36..f1ef3b42d0e8e11984480f4317bf86f0384d1629 100644
--- a/tests/compiler/dart2js/unparser_test.dart
+++ b/tests/compiler/dart2js/unparser_test.dart
@@ -208,6 +208,20 @@ testCombinators() {
   testUnparseTopLevelWithMetadata('export "søhest" hide a,show hide a,show;');
 }
 
+testRedirectingFactoryConstructors() {
+  for (String prefix in ["", "prefix."]) {
+    for (String suffix in ["", ".baz"]) {
+      for (String typeVar in ["", "<T>"]) {
+        for (String constFlag in ["", "const "]) {
+          String declaration =
+              "${constFlag}factory Foo() = ${prefix}Bar${typeVar}$suffix;";
+          testUnparseMember(declaration);
+        }
+      }
+    }
+  }
+}
+
 main() {
   testSignedConstants();
   testGenericTypes();
@@ -225,4 +239,5 @@ main() {
   testPart();
   testPartOf();
   testCombinators();
+  testRedirectingFactoryConstructors();
 }