Use entities in BackendClasses

pkg/compiler/lib/src/compiler.dart

 // Copyright (c) 2012, 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.compiler_base;
 
 import 'dart:async' show EventSink, Future;
 
 import '../compiler_new.dart' as api;
 import 'cache_strategy.dart' show CacheStrategy;
@@ skipping 1170 matching lines @@
 
   @override
   MemberElement findClassMember(ClassElement cls, String name,
       {bool required: true}) {
     cls.ensureResolved(resolution);
     MemberElement member = cls.lookupLocalMember(name);
     if (member == null && required) {
       reporter.internalError(
           cls,
           "The class '${cls}' in '${cls.library.canonicalUri}' does not "
-              "contain required member: '$name'.");
+          "contain required member: '$name'.");
     }
     return member;
   }
 
   @override
   ConstructorElement findConstructor(ClassElement cls, String name,
       {bool required: true}) {
     cls.ensureResolved(resolution);
     ConstructorElement constructor = cls.lookupConstructor(name);
     if (constructor == null && required) {
       reporter.internalError(
           cls,
           "The class '${cls}' in '${cls.library.canonicalUri}' does not "
-              "contain required constructor: '$name'.");
+          "contain required constructor: '$name'.");
     }
     return constructor;
   }
 
   @override
   ClassElement findClass(LibraryElement library, String name,
       {bool required: true}) {
     return _findLibraryMember(library, name, required: required);
   }
 
-  Element _findRequired(LibraryElement library, String name) => _findLibraryMember(library, name);
+  Element _findRequired(LibraryElement library, String name) =>
+      _findLibraryMember(library, name);
 
   Element _findLibraryMember(LibraryElement library, String name,
       {bool required: true}) {
     // If the script of the library is synthesized, the library does not exist
     // and we do not try to load the helpers.
     //
     // This could for example happen if dart:async is disabled, then loading it
     // should not try to find the given element.
     if (library == null || library.isSynthesized) return null;
 
@@ skipping 758 matching lines @@
   _ElementScanner(this.scanner);
   void scanLibrary(LibraryElement library) => scanner.scanLibrary(library);
   void scanUnit(CompilationUnitElement unit) => scanner.scan(unit);
 }
 
 class _EmptyEnvironment implements Environment {
   const _EmptyEnvironment();
 
   String valueOf(String key) => null;
 }