Compute Compiler.proxyConstant on demand.

pkg/compiler/lib/src/resolution/registry.dart

 // Copyright (c) 2014, 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.registry;
 
 import '../common/backend_api.dart' show
     Backend;
 import '../common/registry.dart' show
     Registry;
@@ skipping 592 matching lines @@
   }
 
   void registerAsyncMarker(FunctionElement element) {
     backend.registerAsyncMarker(element, world, this);
   }
 
   void registerAsyncForIn(AsyncForIn node) {
     backend.resolutionCallbacks.onAsyncForIn(node, this);
   }
 
+  void registerIncDecOperation() {
+    backend.resolutionCallbacks.onIncDecOperation(this);
+  }
+
   void registerTryStatement() {
     mapping.containsTryStatement = true;
   }
 }