Move parser helper classes to own files and clean them up.

pkg/analyzer/tool/summary/mini_ast.dart

 // Copyright (c) 2017, 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:front_end/src/fasta/problems.dart'
     show internalProblem, unsupported;
 import 'package:front_end/src/fasta/messages.dart' show Message;
-import 'package:front_end/src/fasta/parser/identifier_context.dart';
-import 'package:front_end/src/fasta/parser/parser.dart';
+import 'package:front_end/src/fasta/parser.dart';
 import 'package:front_end/src/fasta/source/stack_listener.dart';
 import 'package:front_end/src/scanner/token.dart';
 
 /// "Mini AST" representation of a declaration which can accept annotations.
 class AnnotatedNode {
   final Comment documentationComment;
 
   final List<Annotation> metadata;
 
   AnnotatedNode(this.documentationComment, List<Annotation> metadata)
@@ skipping 231 matching lines @@
   }
 
   @override
   void endFieldInitializer(Token assignment, Token token) {
     debugEvent("FieldInitializer");
     pop(); // Expression
   }
 
   @override
   void endFormalParameter(Token thisKeyword, Token nameToken,
-      FormalParameterType kind, MemberKind memberKind) {
+      FormalParameterKind kind, MemberKind memberKind) {
     debugEvent("FormalParameter");
     pop(); // Name
     pop(); // Type
     pop(); // Metadata
     pop(); // Comment
   }
 
   @override
   void endFormalParameters(
       int count, Token beginToken, Token endToken, MemberKind kind) {
@@ skipping 199 matching lines @@
   final String name;
 
   final List<TypeName> typeArguments;
 
   TypeName(this.name, this.typeArguments);
 }
 
 /// "Mini AST" representation of an expression which summary code generation
 /// need not be concerned about.
 class UnknownExpression extends Expression {}