Handle signature types and fields in kernel_impact

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

Index: pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
diff --git a/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart b/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
index 8682d351d131b39628b3b02079cbcc49e6697177..94b9ad4caea10a0c166ec31a3df24caebb8fa2ad 100644
--- a/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
+++ b/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
@@ -35,11 +35,15 @@ class KernelAstAdapter {
       this._nodeToAst,
       this._nodeToElement,
       Map<FunctionElement, ir.Member> functions,
+      Map<FieldElement, ir.Field> fields,
       Map<ClassElement, ir.Class> classes,
       Map<LibraryElement, ir.Library> libraries) {
     for (FunctionElement functionElement in functions.keys) {
       _nodeToElement[functions[functionElement]] = functionElement;
     }
+    for (FieldElement fieldElement in fields.keys) {
+      _nodeToElement[fields[fieldElement]] = fieldElement;
+    }
     for (ClassElement classElement in classes.keys) {
       _nodeToElement[classes[classElement]] = classElement;
     }