dart2js: Pass type information to constructor rather than add later.

pkg/compiler/lib/src/js_backend/backend.dart

Index: pkg/compiler/lib/src/js_backend/backend.dart
diff --git a/pkg/compiler/lib/src/js_backend/backend.dart b/pkg/compiler/lib/src/js_backend/backend.dart
index b79556e5e4187959d86c68965a39ea7851c8ac39..b9c86b1ab0c0452e410b38f0aa5c9b3983d3e6ee 100644
--- a/pkg/compiler/lib/src/js_backend/backend.dart
+++ b/pkg/compiler/lib/src/js_backend/backend.dart
@@ -1113,7 +1113,7 @@ class JavaScriptBackend extends Backend {
         type.isFunctionType ? coreTypes.functionType : type;
     if (type is InterfaceType) {
       registry.registerInstantiation(instantiatedType);
-      if (!type.treatAsRaw && classNeedsRti(type.element)) {
+      if (classNeedsRti(type.element)) {
         registry.registerStaticUse(new StaticUse.staticInvoke(
             // TODO(johnniwinther): Find the right [CallStructure].
             helpers.setRuntimeTypeInfo,
@@ -1486,8 +1486,10 @@ class JavaScriptBackend extends Backend {
   }
 
   bool classNeedsRti(ClassElement cls) {
-    return rti.classesNeedingRti.contains(cls.declaration) ||
-        compiler.enabledRuntimeType;
+    if (cls.rawType.typeArguments.isEmpty) return false;
+    if (rti.classesNeedingRti.contains(cls.declaration)) return true;
+    if (compiler.enabledRuntimeType) return true;  // Needed e.g. to print.
+    return false;
   }
 
   bool isComplexNoSuchMethod(FunctionElement element) =>