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

pkg/compiler/lib/src/parser/node_listener.dart

 // Copyright (c) 2015, 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.
 
 library dart2js.parser.node_listener;
 
-import 'package:front_end/src/fasta/parser/parser.dart'
-    show FormalParameterType, MemberKind;
-import 'package:front_end/src/fasta/parser/identifier_context.dart'
-    show IdentifierContext;
+import 'package:front_end/src/fasta/parser.dart'
+    show FormalParameterKind, IdentifierContext, MemberKind;
 import 'package:front_end/src/fasta/scanner.dart' show Token;
 import 'package:front_end/src/scanner/token.dart' show TokenType;
 
 import '../common.dart';
 import '../elements/elements.dart' show CompilationUnitElement;
 import '../tree/tree.dart';
 import '../util/util.dart' show Link;
 import 'element_listener.dart' show ElementListener, ScannerOptions;
 
-import 'package:front_end/src/fasta/parser/parser.dart' as fasta show Assert;
+import 'package:front_end/src/fasta/parser.dart' as fasta show Assert;
 
 class NodeListener extends ElementListener {
   NodeListener(ScannerOptions scannerOptions, DiagnosticReporter reporter,
       CompilationUnitElement element)
       : super(scannerOptions, reporter, element, null);
 
   @override
   void addLibraryTag(LibraryTag tag) {
     pushNode(tag);
   }
@@ skipping 194 matching lines @@
     NodeList typeVariables = popNode();
     Identifier name = popNode();
     TypeAnnotation type = popNode();
     Modifiers modifiers = popNode();
     pushNode(new FunctionExpression(name, typeVariables, formals, body, type,
         modifiers, null, getOrSet, asyncModifier));
   }
 
   @override
   void endFormalParameter(Token thisKeyword, Token nameToken,
-      FormalParameterType kind, MemberKind memberKind) {
+      FormalParameterKind kind, MemberKind memberKind) {
     Expression name = popNode();
     if (thisKeyword != null) {
       Identifier thisIdentifier = new Identifier(thisKeyword);
       if (name.asSend() == null) {
         name = new Send(thisIdentifier, name);
       } else {
         name = name.asSend().copyWithReceiver(thisIdentifier, false);
       }
     }
     TypeAnnotation type = popNode();
@@ skipping 822 matching lines @@
     }
     lastErrorWasNativeFunctionBody = false;
   }
 
   void internalError({Token token, Node node}) {
     // TODO(ahe): This should call reporter.internalError.
     Spannable spannable = (token == null) ? node : token;
     failedAt(spannable, 'Internal error in parser.');
   }
 }