dart2js cps: Refactor and optimize string concatenations.

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

 // Copyright (c) 2014, 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.constants.expressions;
 
 import '../constants/constant_system.dart';
 import '../core_types.dart';
 import '../dart2jslib.dart' show assertDebugMode, Compiler;
 import '../dart_types.dart';
@@ skipping 1513 matching lines @@
   R visitIntFromEnvironment(IntFromEnvironmentConstantExpression exp,
                             A context);
   R visitStringFromEnvironment(StringFromEnvironmentConstantExpression exp,
                                A context);
   R visitDeferred(DeferredConstantExpression exp, A context);
 
   R visitPositional(PositionalArgumentReference exp, A context);
   R visitNamed(NamedArgumentReference exp, A context);
 }
 
-/// Represents the declaration of a constant [element] with value [expression].
-// TODO(johnniwinther): Where does this class belong?
-class ConstDeclaration {
-  final VariableElement element;
-  final ConstantExpression expression;
-
-  ConstDeclaration(this.element, this.expression);
-}
-
 class ConstExpPrinter extends ConstantExpressionVisitor {
   final StringBuffer sb = new StringBuffer();
 
   void write(ConstantExpression parent,
              ConstantExpression child,
              {bool leftAssociative: true}) {
     if (child.precedence < parent.precedence ||
         !leftAssociative && child.precedence == parent.precedence) {
       sb.write('(');
       child.accept(this);
@@ skipping 251 matching lines @@
     visit(exp.name);
     if (exp.defaultValue != null) {
       sb.write(', defaultValue: ');
       visit(exp.defaultValue);
     }
     sb.write(')');
   }
 
   String toString() => sb.toString();
 }