dart2js: patch file support cleanup

pkg/compiler/lib/src/js_backend/backend.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 js_backend.backend;
 
 import '../common.dart';
 import '../common/backend_api.dart'
     show ForeignResolver, NativeRegistry, ImpactTransformer;
 import '../common/codegen.dart' show CodegenImpact, CodegenWorkItem;
@@ skipping 290 matching lines @@
 }
 
 class JavaScriptBackend {
   static const String JS = 'JS';
   static const String JS_BUILTIN = 'JS_BUILTIN';
   static const String JS_EMBEDDED_GLOBAL = 'JS_EMBEDDED_GLOBAL';
   static const String JS_INTERCEPTOR_CONSTANT = 'JS_INTERCEPTOR_CONSTANT';
 
   final Compiler compiler;
 
-  String get patchVersion => emitter.patchVersion;
-
   /// Returns true if the backend supports reflection.
   bool get supportsReflection => emitter.supportsReflection;
 
   final Annotations annotations;
 
   /// Set of classes that need to be considered for reflection although not
   /// otherwise visible during resolution.
   Iterable<ClassEntity> get classesRequiredForReflection {
     // TODO(herhut): Clean this up when classes needed for rti are tracked.
     return [commonElements.closureClass, commonElements.jsIndexableClass];
@@ skipping 1141 matching lines @@
 
   bool canUseAliasedSuperMember(MemberEntity member, Selector selector) {
     return !selector.isGetter;
   }
 
   /// Returns `true` if [member] is called from a subclass via `super`.
   bool isAliasedSuperMember(MemberEntity member) {
     return _aliasedSuperMembers.contains(member);
   }
 }