Introduce BackendImpact to separate enqueueing from data.

pkg/compiler/lib/src/resolution/members.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.members;
 
 import '../common/names.dart' show
     Selectors;
 import '../compiler.dart' show
     Compiler;
@@ skipping 3863 matching lines @@
             registry.registerConstSymbol(nameString);
           }
         }
       } else {
         if (!compiler.mirrorUsageAnalyzerTask.hasMirrorUsage(
                 enclosingElement)) {
           reporter.reportHintMessage(
               node.newToken, MessageKind.NON_CONST_BLOAT,
               {'name': compiler.symbolClass.name});
         }
-        registry.registerNewSymbol();
       }
     } else if (isMirrorsUsedConstant) {
       compiler.mirrorUsageAnalyzerTask.validate(node, registry.mapping);
     }
     if (node.isConst) {
       analyzeConstantDeferred(node);
 
       // TODO(johnniwinther): Compute this in the [ConstructorResolver].
       // Check that the constructor is not deferred.
       Send send = node.send.selector.asSend();
@@ skipping 796 matching lines @@
     }
     return const NoneResult();
   }
 }
 
 /// Looks up [name] in [scope] and unwraps the result.
 Element lookupInScope(DiagnosticReporter reporter, Node node,
                       Scope scope, String name) {
   return Elements.unwrap(scope.lookup(name), reporter, node);
 }