Make the universe parts into small libraries.

pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.ir_builder;
 
 import '../common/names.dart' show
     Names,
     Selectors;
 import '../compile_time_constants.dart' show
     BackendConstantEnvironment;
 import '../constants/constant_system.dart';
 import '../constants/values.dart' show
     ConstantValue,
     PrimitiveConstantValue;
 import '../dart_types.dart';
 import '../diagnostics/invariant.dart' show
     invariant;
 import '../elements/elements.dart';
 import '../io/source_information.dart';
 import '../tree/tree.dart' as ast;
 import '../types/types.dart' show
     TypeMask;
 import '../closure.dart' hide ClosureScope;
-import '../universe/universe.dart' show
-    CallStructure,
+import '../universe/call_structure.dart' show
+    CallStructure;
+import '../universe/selector.dart' show
     Selector,
     SelectorKind;
 import 'cps_ir_nodes.dart' as ir;
 import 'cps_ir_builder_task.dart' show
     DartCapturedVariables,
     GlobalProgramInformation;
 
 import '../common.dart' as types show
     TypeMask;
 import '../js/js.dart' as js show Template, js, LiteralStatement;
@@ skipping 2842 matching lines @@
 }
 
 class SwitchCaseInfo {
   final List<ir.Primitive> constants = <ir.Primitive>[];
   final SubbuildFunction buildBody;
 
   SwitchCaseInfo(this.buildBody);
 
   void addConstant(ir.Primitive constant) => constants.add(constant);
 }