Remove Frontend interface

pkg/compiler/lib/src/common/resolution.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.common.resolution;
 
 import '../common.dart';
 import '../compile_time_constants.dart';
 import '../constants/expressions.dart' show ConstantExpression;
 import '../constants/values.dart' show ConstantValue;
@@ skipping 58 matching lines @@
   Iterable<Feature> get features => const <Feature>[];
   Iterable<MapLiteralUse> get mapLiterals => const <MapLiteralUse>[];
   Iterable<ListLiteralUse> get listLiterals => const <ListLiteralUse>[];
   Iterable<String> get constSymbolNames => const <String>[];
   Iterable<ConstantExpression> get constantLiterals =>
       const <ConstantExpression>[];
 
   Iterable<dynamic> get nativeData => const <dynamic>[];
 }
 
-/// Interface for the accessing the front-end analysis.
-// TODO(johnniwinther): Find a better name for this.
-abstract class Frontend {
-  /// Returns the [ResolutionImpact] for [element].
-  ResolutionImpact getResolutionImpact(Element element);
-}
-
 /// Interface defining target-specific behavior for resolution.
 abstract class Target {
   /// Returns `true` if [library] is a target specific library whose members
   /// have special treatment, such as being allowed to extends blacklisted
   /// classes or members being eagerly resolved.
   bool isTargetSpecificLibrary(LibraryElement element);
 
   /// Resolve target specific information for [element] and register it with
   /// [registry].
   void resolveNativeMember(MemberElement element, NativeRegistry registry) {}
@@ skipping 23 matching lines @@
 
   /// Returns `true` if [element] is a foreign element, that is, that the
   /// backend has specialized handling for the element.
   bool isForeign(Element element) => false;
 
   /// Returns `true` if this target supports async/await.
   bool get supportsAsyncAwait => true;
 }
 
 // TODO(johnniwinther): Rename to `Resolver` or `ResolverContext`.
-abstract class Resolution implements Frontend {
+abstract class Resolution {
   ParsingContext get parsingContext;
   DiagnosticReporter get reporter;
   CommonElements get commonElements;
   Types get types;
   Target get target;
   ResolverTask get resolver;
   ResolutionEnqueuer get enqueuer;
   CompilerOptions get options;
   IdGenerator get idGenerator;
   ConstantEnvironment get constants;
@@ skipping 118 matching lines @@
       if (cls.isPatch) {
         patchParser.parsePatchClassNode(cls);
       }
     });
   }
 
   @override
   ScannerOptions getScannerOptionsFor(Element element) => new ScannerOptions(
       canUseNative: backend.canLibraryUseNative(element.library));
 }