Handle signature types and fields in kernel_impact

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 'dart:async' show Future;
 
 import 'package:js_runtime/shared/embedded_names.dart' as embeddedNames;
 
@@ skipping 2802 matching lines @@
           break;
         case Feature.COMPILE_TIME_ERROR:
           if (backend.compiler.options.generateCodeWithCompileTimeErrors) {
             // TODO(johnniwinther): This should have its own uncatchable error.
             registerBackendImpact(transformed, impacts.throwRuntimeError);
           }
           break;
         case Feature.FALL_THROUGH_ERROR:
           registerBackendImpact(transformed, impacts.fallThroughError);
           break;
+        case Feature.FIELD_WITHOUT_INITIALIZER:
+          transformed.registerTypeUse(
+              new TypeUse.instantiation(backend.coreTypes.nullType));
+          registerBackendImpact(transformed, impacts.nullLiteral);
+          break;
         case Feature.INC_DEC_OPERATION:
           registerBackendImpact(transformed, impacts.incDecOperation);
           break;
         case Feature.LAZY_FIELD:
           registerBackendImpact(transformed, impacts.lazyField);
           break;
         case Feature.STACK_TRACE_IN_CATCH:
           registerBackendImpact(transformed, impacts.stackTraceInCatch);
           break;
         case Feature.STRING_INTERPOLATION:
@@ skipping 381 matching lines @@
 
   @override
   void onImpactUsed(ImpactUseCase impactUse) {
     if (impactUse == DeferredLoadTask.IMPACT_USE && !supportSerialization) {
       // TODO(johnniwinther): Allow emptying when serialization has been
       // performed.
       resolution.emptyCache();
     }
   }
 }