Make the universe parts into small libraries.

pkg/compiler/lib/src/constants/constant_constructors.dart

Index: pkg/compiler/lib/src/constants/constant_constructors.dart
diff --git a/pkg/compiler/lib/src/constants/constant_constructors.dart b/pkg/compiler/lib/src/constants/constant_constructors.dart
index e3773cfe4fa1754b524946881b8c9da8fc12051c..fa774e8b36acb224e0eb527e867cd826b174ed8f 100644
--- a/pkg/compiler/lib/src/constants/constant_constructors.dart
+++ b/pkg/compiler/lib/src/constants/constant_constructors.dart
@@ -18,7 +18,8 @@ import '../resolution/send_structure.dart';
 import '../resolution/tree_elements.dart' show
     TreeElements;
 import '../tree/tree.dart';
-import '../universe/universe.dart' show CallStructure;
+import '../universe/call_structure.dart' show
+    CallStructure;
 import 'constructors.dart';
 import 'expressions.dart';