Make the universe parts into small libraries.

pkg/compiler/lib/src/js_backend/codegen/unsugar.dart

 library dart2js.unsugar_cps;
 
 import '../../cps_ir/cps_ir_nodes.dart';
 
 import '../../cps_ir/optimizers.dart' show ParentVisitor;
 import '../../constants/values.dart';
 import '../../elements/elements.dart';
 import '../../io/source_information.dart';
 import '../../js_backend/codegen/glue.dart';
-import '../../universe/universe.dart' show Selector;
+import '../../universe/selector.dart' show Selector;
 import '../../cps_ir/cps_ir_builder.dart' show ThisParameterLocal;
 
 class ExplicitReceiverParameterEntity implements Local {
   String get name => 'receiver';
   final ExecutableElement executableContext;
   ExplicitReceiverParameterEntity(this.executableContext);
   toString() => 'ExplicitReceiverParameterEntity($executableContext)';
 }
 
 /// Suggested name for an interceptor.
@@ skipping 24 matching lines @@
   // In a catch block, rethrow implicitly throws the block's exception
   // parameter.  This is the exception parameter when nested in a catch
   // block and null otherwise.
   Parameter _exceptionParameter = null;
 
   UnsugarVisitor(this._glue);
 
   bool methodUsesReceiverArgument(FunctionElement function) {
     assert(_glue.isInterceptedMethod(function));
     ClassElement clazz = function.enclosingClass.declaration;
-    return _glue.isInterceptorClass(clazz) || 
+    return _glue.isInterceptorClass(clazz) ||
            _glue.isUsedAsMixin(clazz);
   }
 
   void rewrite(FunctionDefinition function) {
     thisParameter = function.thisParameter;
     bool inInterceptedMethod = _glue.isInterceptedMethod(function.element);
 
     if (function.element.name == '==' &&
         function.parameters.length == 1 &&
         !_glue.operatorEqHandlesNullArgument(function.element)) {
@@ skipping 209 matching lines @@
       insertLetPrim(newReceiver, contBinding);
     }
     node.arguments.insert(0, node.receiver);
     node.receiver = new Reference<Primitive>(newReceiver);
   }
 
   processInterceptor(Interceptor node) {
     _glue.registerSpecializedGetInterceptor(node.interceptedClasses);
   }
 }