Handle const Symbol(...) in kernel_impact

pkg/compiler/lib/src/kernel/element_map.dart

Index: pkg/compiler/lib/src/kernel/element_map.dart
diff --git a/pkg/compiler/lib/src/kernel/element_map.dart b/pkg/compiler/lib/src/kernel/element_map.dart
index 22256550ac69816cf7c710e29b5f85cc8346951e..d7aa2102f268a7769c3cc13ba563686b508c8b59 100644
--- a/pkg/compiler/lib/src/kernel/element_map.dart
+++ b/pkg/compiler/lib/src/kernel/element_map.dart
@@ -77,8 +77,7 @@ class KernelToElementMap extends KernelElementAdapterMixin {
     _elementEnvironment = new KernelElementEnvironment(this);
     _commonElements = new CommonElements(_elementEnvironment);
     _constantEnvironment = new KernelConstantEnvironment(this);
-    _nativeBehaviorBuilder =
-        new KernelBehaviorBuilder(_commonElements, _constantEnvironment);
+    _nativeBehaviorBuilder = new KernelBehaviorBuilder(_commonElements);
     _types = new _KernelDartTypes(this);
     _typeConverter = new DartTypeConverter(this);
   }
@@ -124,6 +123,11 @@ class KernelToElementMap extends KernelElementAdapterMixin {
   @override
   native.BehaviorBuilder get nativeBehaviorBuilder => _nativeBehaviorBuilder;
 
+  @override
+  ConstantValue computeConstantValue(ConstantExpression constant) {
+    return _constantEnvironment.getConstantValue(constant);
+  }
+
   LibraryEntity lookupLibrary(Uri uri) {
     _KLibraryEnv libraryEnv = _env.lookupLibrary(uri);
     if (libraryEnv == null) return null;
@@ -194,7 +198,7 @@ class KernelToElementMap extends KernelElementAdapterMixin {
     });
   }
 
-  Iterable<ConstantExpression> _getClassMetadata(KClass cls) {
+  Iterable<ConstantValue> _getClassMetadata(KClass cls) {
     return _classEnvs[cls.classIndex].getMetadata(this);
   }
 
@@ -732,7 +736,7 @@ class _KClassEnv {
   Map<String, ir.Member> _memberMap;
   Map<String, ir.Member> _setterMap;
 
-  Iterable<ConstantExpression> _metadata;
+  Iterable<ConstantValue> _metadata;
 
   _KClassEnv(this.cls)
       // TODO(johnniwinther): Change this to use a property on [cls] when such
@@ -801,7 +805,7 @@ class _KClassEnv {
     }
   }
 
-  Iterable<ConstantExpression> getMetadata(KernelToElementMap elementMap) {
+  Iterable<ConstantValue> getMetadata(KernelToElementMap elementMap) {
     if (_metadata == null) {
       _metadata = elementMap.getMetadata(cls.annotations);
     }
@@ -811,7 +815,7 @@ class _KClassEnv {
 
 class _MemberData {
   final ir.Member node;
-  Iterable<ConstantExpression> _metadata;
+  Iterable<ConstantValue> _metadata;
 
   _MemberData(this.node);
 
@@ -819,7 +823,7 @@ class _MemberData {
     return buildKernelImpact(node, elementMap);
   }
 
-  Iterable<ConstantExpression> getMetadata(KernelToElementMap elementMap) {
+  Iterable<ConstantValue> getMetadata(KernelToElementMap elementMap) {
     return _metadata ??= elementMap.getMetadata(node.annotations);
   }
 }
@@ -1049,12 +1053,8 @@ class KernelElementEnvironment implements ElementEnvironment {
 
   @override
   Iterable<ConstantValue> getMemberMetadata(KMember member) {
-    List<ConstantValue> values = <ConstantValue>[];
     _MemberData memberData = elementMap._memberList[member.memberIndex];
-    for (ConstantExpression constant in memberData.getMetadata(elementMap)) {
-      values.add(elementMap.constantEnvironment.getConstantValue(constant));
-    }
-    return values;
+    return memberData.getMetadata(elementMap);
   }
 }
 
@@ -1136,12 +1136,8 @@ class DartTypeConverter extends ir.DartTypeVisitor<DartType> {
 /// [native.BehaviorBuilder] for kernel based elements.
 class KernelBehaviorBuilder extends native.BehaviorBuilder {
   final CommonElements commonElements;
-  final ConstantEnvironment constants;
 
-  KernelBehaviorBuilder(
-    this.commonElements,
-    this.constants,
-  );
+  KernelBehaviorBuilder(this.commonElements);
 
   @override
   bool get trustJSInteropTypeAnnotations {