Enables codegen support in polymer

pkg/code_transformers/lib/src/resolver_impl.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 code_transformer.src.resolver_impl;
 
 import 'dart:async';
 import 'package:analyzer/analyzer.dart' show parseCompilationUnit;
-import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/ast.dart' hide ConstantEvaluator;
+import 'package:analyzer/src/generated/constant.dart' show ConstantEvaluator,
+       EvaluationResult;
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/java_io.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/sdk.dart' show DartSdk;
 import 'package:analyzer/src/generated/sdk_io.dart' show DirectoryBasedDartSdk;
 import 'package:analyzer/src/generated/source.dart';
 import 'package:barback/barback.dart';
 import 'package:code_transformers/assets.dart';
 import 'package:path/path.dart' as native_path;
 import 'package:source_maps/refactor.dart';
 import 'package:source_maps/span.dart' show SourceFile, Span;
 
 import 'resolver.dart';
 
 // We should always be using url paths here since it's always Dart/pub code.
 final path = native_path.url;
 
 /// Resolves and updates an AST based on Barback-based assets.
 ///
 /// This also provides a handful of useful APIs for traversing and working
 /// with the resolved AST.
 class ResolverImpl implements Resolver {
   /// Cache of all asset sources currently referenced.
   final Map<AssetId, _AssetBasedSource> sources =
       <AssetId, _AssetBasedSource>{};
 
-  final AnalysisContext _context =
+  final InternalAnalysisContext _context =
       AnalysisEngine.instance.createAnalysisContext();
 
   /// Transform for which this is currently updating, or null when not updating.
   Transform _currentTransform;
 
   /// The currently resolved entry libraries, or null if nothing is resolved.
   List<LibraryElement> _entryLibraries;
   Set<LibraryElement> _libraries;
 
   /// Future indicating when this resolver is done in the current phase.
@@ skipping 166 matching lines @@
     var name = dotIndex == -1 ?
         fnName : fnName.substring(dotIndex + 1);
 
     return libraries.where((lib) => lib.name == libraryName)
         .expand((lib) => lib.units)
         .expand((unit) => unit.functions)
         .firstWhere((fn) => fn.name == name,
             orElse: () => null);
   }
 
+  EvaluationResult evaluateConstant(
+      LibraryElement library, Expression expression) {
+    return new ConstantEvaluator(library.source, _context.typeProvider)
+        .evaluate(expression);
+  }
+
   Uri getImportUri(LibraryElement lib, {AssetId from}) =>
       _getSourceUri(lib, from: from);
 
 
   /// Similar to getImportUri but will get the part URI for parts rather than
   /// the library URI.
   Uri _getSourceUri(Element element, {AssetId from}) {
     var source = element.source;
     if (source is _AssetBasedSource) {
       return source.getSourceUri(from);
@@ skipping 366 matching lines @@
 
   void apply(ChangeSet changeSet) {
     if (!source.updateContents(content)) return;
     if (source._revision == 1 && source._contents != null) {
       changeSet.addedSource(source);
     } else {
       changeSet.changedSource(source);
     }
   }
 }