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

pkg/analyzer/tool/summary/mini_ast.dart

Index: pkg/analyzer/tool/summary/mini_ast.dart
diff --git a/pkg/analyzer/tool/summary/mini_ast.dart b/pkg/analyzer/tool/summary/mini_ast.dart
index 2408ea8731a17a467dc17b7acf46aeac10c6107c..1be9a900958c0d9c50b0e41903313eaaf5e6cb96 100644
--- a/pkg/analyzer/tool/summary/mini_ast.dart
+++ b/pkg/analyzer/tool/summary/mini_ast.dart
@@ -5,8 +5,7 @@
 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';
 
@@ -258,7 +257,7 @@ class MiniAstBuilder extends StackListener {
 
   @override
   void endFormalParameter(Token thisKeyword, Token nameToken,
-      FormalParameterType kind, MemberKind memberKind) {
+      FormalParameterKind kind, MemberKind memberKind) {
     debugEvent("FormalParameter");
     pop(); // Name
     pop(); // Type