dart2js: set effective target for patched constructors

pkg/compiler/lib/src/elements/modelx.dart

Index: pkg/compiler/lib/src/elements/modelx.dart
diff --git a/pkg/compiler/lib/src/elements/modelx.dart b/pkg/compiler/lib/src/elements/modelx.dart
index f1d4c5bb04fe6dd1ea4afdecb656901fe57a8e12..1073644d1f6d21773cc9eff098e14226d270c438 100644
--- a/pkg/compiler/lib/src/elements/modelx.dart
+++ b/pkg/compiler/lib/src/elements/modelx.dart
@@ -2203,7 +2203,11 @@ abstract class ConstructorElementX extends FunctionElementX
       return immediateRedirectionTarget;
     }
     assert(!isRedirectingFactory || internalEffectiveTarget != null);
-    return isRedirectingFactory ? internalEffectiveTarget : this;
+    if (isRedirectingFactory) return internalEffectiveTarget;
+    if (isPatched) {

[Johnni Winther, 2015/10/06 10:38:14]

Why is this needed?

[Harry Terkelsen, 2015/10/12 18:17:44]

There are targets that are patched but are not redirecting factories, so we need
to check that internalEffectiveTarget is set (by the method which resolves
chains of redirecting factories)

+      return internalEffectiveTarget ?? this;
+    }
+    return this;
   }
 
   InterfaceType computeEffectiveTargetType(InterfaceType newType) {