Store constant variable initializers in elements.

pkg/compiler/lib/src/mirrors/dart2js_member_mirrors.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.
 
 part of dart2js.mirrors;
 
 //------------------------------------------------------------------------------
 // Member mirrors implementation.
 //------------------------------------------------------------------------------
 
@@ skipping 172 matching lines @@
 
   bool get isFinal => false;
 
   bool get isConst => false;
 
   InstanceMirror get defaultValue {
     if (hasDefaultValue) {
       // TODO(johnniwinther): Get the constant from the [TreeElements]
       // associated with the enclosing method.
       ParameterElement parameter = _element;
-      ConstantExpression constant =
-          mirrorSystem.compiler.constants.getConstantForVariable(parameter);
+      ConstantExpression constant = parameter.constant;
       assert(invariant(parameter, constant != null,
           message: "Missing constant for parameter "
               "$parameter with default value."));
       return _convertConstantToInstanceMirror(mirrorSystem, constant,
           mirrorSystem.compiler.constants.getConstantValue(constant));
     }
     return null;
   }
 
   bool get hasDefaultValue {
@@ skipping 14 matching lines @@
       InitializingFormalElement element, bool isOptional, bool isNamed)
       : super._normal(method, element, isOptional, isNamed);
 
   InitializingFormalElement get _fieldParameterElement => _element;
 
   bool get isInitializingFormal => true;
 
   VariableMirror get initializedField =>
       new Dart2JsFieldMirror(owner.owner, _fieldParameterElement.fieldElement);
 }