Handle const Symbol(...) in kernel_impact

pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart

 // Copyright (c) 2016, 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.
 
 import 'package:js_runtime/shared/embedded_names.dart';
 import 'package:kernel/ast.dart' as ir;
 
 import '../closure.dart';
 import '../common.dart';
 import '../compiler.dart';
@@ skipping 67 matching lines @@
     }
     for (LocalFunctionElement localFunction in kernel.localFunctions.keys) {
       _nodeToElement[kernel.localFunctions[localFunction]] = localFunction;
     }
     for (TypeVariableElement typeVariable in kernel.typeParameters.keys) {
       _nodeToElement[kernel.typeParameters[typeVariable]] = typeVariable;
     }
     _typeConverter = new DartTypeConverter(this);
   }
 
+  @override
+  ConstantValue computeConstantValue(ConstantExpression constant) {
+    return _compiler.constants.getConstantValue(constant);
+  }
+
   /// Called to find the corresponding Kernel element for a particular Element
   /// before traversing over it with a Kernel visitor.
   ir.Node getInitialKernelNode(Element originTarget) {
     ir.Node target;
     if (originTarget.isPatch) {
       originTarget = originTarget.origin;
     }
     if (originTarget is FunctionElement) {
       if (originTarget is ConstructorBodyElement) {
         ConstructorBodyElement body = originTarget;
@@ skipping 729 matching lines @@
       JumpTarget continueTarget =
           astAdapter.getJumpTarget(switchCase, isContinueTarget: true);
       assert(continueTarget is KernelJumpTarget);
       targetIndexMap[continueTarget] = switchIndex;
       assert(builder.jumpTargets[continueTarget] == null);
       builder.jumpTargets[continueTarget] = this;
       switchIndex++;
     }
   }
 }