Use Feature directly in resolution.

pkg/compiler/lib/src/resolution/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.resolution;
 
 import 'dart:collection' show Queue;
 
 import '../common.dart';
 import '../common/names.dart' show
     Identifiers;
 import '../common/resolution.dart' show
+    Feature,
     Parsing,
     Resolution,
     ResolutionImpact;
 import '../common/tasks.dart' show
     CompilerTask,
     DeferredAction;
 import '../compiler.dart' show
     Compiler;
 import '../compile_time_constants.dart' show
     ConstantCompiler;
@@ skipping 159 matching lines @@
 
         }
         if (functionExpression.body.asReturn() != null &&
             element.asyncMarker.isYielding) {
           reporter.reportErrorMessage(
               asyncModifier,
               MessageKind.YIELDING_MODIFIER_ON_ARROW_BODY,
               {'modifier': element.asyncMarker});
         }
       }
-      registry.registerAsyncMarker(element);
       switch (element.asyncMarker) {
       case AsyncMarker.ASYNC:
+        registry.registerFeature(Feature.ASYNC);
         coreClasses.futureClass.ensureResolved(resolution);
         break;
       case AsyncMarker.ASYNC_STAR:
+        registry.registerFeature(Feature.ASYNC_STAR);
         coreClasses.streamClass.ensureResolved(resolution);
         break;
       case AsyncMarker.SYNC_STAR:
+        registry.registerFeature(Feature.SYNC_STAR);
         coreClasses.iterableClass.ensureResolved(resolution);
         break;
       }
     }
   }
 
   bool _isNativeClassOrExtendsNativeClass(ClassElement classElement) {
     assert(classElement != null);
     while (classElement != null) {
       if (compiler.backend.isNative(classElement)) return true;
@@ skipping 179 matching lines @@
         if (element.modifiers.isConst) {
           element.constant = constantCompiler.compileConstant(element);
         } else {
           constantCompiler.compileVariable(element);
         }
       });
       if (initializer != null) {
         if (!element.modifiers.isConst) {
           // TODO(johnniwinther): Determine the const-ness eagerly to avoid
           // unnecessary registrations.
-          registry.registerLazyField();
+          registry.registerFeature(Feature.LAZY_FIELD);
         }
       }
     }
 
     // Perform various checks as side effect of "computing" the type.
     element.computeType(resolution);
 
     return registry.worldImpact;
   }
 
@@ skipping 683 matching lines @@
   TreeElements get treeElements {
     assert(invariant(this, _treeElements !=null,
         message: "TreeElements have not been computed for $this."));
     return _treeElements;
   }
 
   void reuseElement() {
     _treeElements = null;
   }
 }