[cfe] Add GetterDeclaration and SetterDeclaration

In preparation for handling getter/setter patches through fragments

Change-Id: I25778f96df35856f84654949eb9dc8ce65a37bac
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/416560
Reviewed-by: Jens Johansen <[email protected]>
Commit-Queue: Johnni Winther <[email protected]>

Author: johnniwinther

pkg/front_end/lib/src/fragment/enum_element.dart

@@ -133,7 +133,7 @@ class EnumElementFragment
       required bool createFileUriExpression}) {
     BodyBuilderContext bodyBuilderContext = createBodyBuilderContext();
     for (Annotatable annotatable in annotatables) {
-      _buildMetadataForOutlineExpressions(libraryBuilder, enclosingScope,
+      buildMetadataForOutlineExpressions(libraryBuilder, enclosingScope,
           bodyBuilderContext, annotatable, metadata,
           fileUri: fileUri, createFileUriExpression: createFileUriExpression);
     }

pkg/front_end/lib/src/fragment/field.dart

@@ -298,7 +298,7 @@ class FieldFragment
       required bool createFileUriExpression}) {
     BodyBuilderContext bodyBuilderContext = createBodyBuilderContext();
     for (Annotatable annotatable in annotatables) {
-      _buildMetadataForOutlineExpressions(libraryBuilder, enclosingScope,
+      buildMetadataForOutlineExpressions(libraryBuilder, enclosingScope,
           bodyBuilderContext, annotatable, metadata,
           fileUri: fileUri, createFileUriExpression: createFileUriExpression);
     }

pkg/front_end/lib/src/fragment/fragment.dart

@@ -62,6 +62,10 @@ import '../type_inference/type_inference_engine.dart';
 import '../type_inference/type_inferrer.dart';
 import '../type_inference/type_schema.dart';
 import 'constructor/declaration.dart';
+import 'getter/declaration.dart';
+import 'getter/encoding.dart';
+import 'setter/declaration.dart';
+import 'setter/encoding.dart';
 
 part 'class.dart';
 part 'class/declaration.dart';