Add toStructuredText to ConstantExpression and align method names with ConstantValue

pkg/compiler/lib/src/resolution/resolution_result.dart

 // Copyright (c) 2015, 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.resolution.result;
 
 import '../constants/expressions.dart';
 import '../dart_types.dart';
 import '../elements/elements.dart';
 import '../tree/tree.dart';
@@ skipping 72 matching lines @@
 
   /// Creates a result for the [constant] expression. [node] is provided for
   /// error reporting on the constant and [element] is provided if the
   /// expression additionally serves an [Element] like [ElementResult].
   ConstantResult(this.node, this.constant, {this.element});
 
   bool get isConstant => true;
 
   ResultKind get kind => ResultKind.CONSTANT;
 
-  String toString() => 'ConstantResult(${constant.getText()})';
+  String toString() => 'ConstantResult(${constant.toDartText()})';
 }
 
 class NoneResult extends ResolutionResult {
   const NoneResult();
 
   ResultKind get kind => ResultKind.NONE;
 
   String toString() => 'NoneResult()';
 }
 
@@ skipping 14 matching lines @@
 
   /// Returns the list of [ConstantExpression]s for each of the arguments. If
   /// [isValidAsConstant] is `false`, `null` is returned.
   List<ConstantExpression> get constantArguments {
     if (!isValidAsConstant) return null;
     return argumentResults.map((ResolutionResult result) {
       return result.constant;
     }).toList();
   }
 }