merge PrecedenceInfo into TokenType and update all refs

pkg/compiler/lib/src/tree/nodes.dart

 // Copyright (c) 2012, 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 'dart:collection' show IterableMixin;
 
-import '../common.dart';
-import '../elements/elements.dart' show MetadataAnnotation;
-import 'package:front_end/src/fasta/scanner/precedence.dart' as Precedence
-    show FUNCTION_INFO;
+import 'package:front_end/src/fasta/fasta_codes.dart' show FastaMessage;
 import 'package:front_end/src/fasta/scanner.dart' show BeginGroupToken, Token;
 import 'package:front_end/src/fasta/scanner/token_constants.dart' as Tokens
     show PLUS_TOKEN;
 import 'package:front_end/src/fasta/scanner/characters.dart';
+import 'package:front_end/src/scanner/token.dart' show TokenType;
+
+import '../common.dart';
+import '../elements/elements.dart' show MetadataAnnotation;
 import '../util/util.dart';
 import 'dartstring.dart';
 import 'prettyprint.dart';
 import 'unparser.dart';
-import 'package:front_end/src/fasta/fasta_codes.dart' show FastaMessage;
 
 abstract class Visitor<R> {
   const Visitor();
 
   R visitNode(Node node);
 
   R visitAssert(Assert node) => visitStatement(node);
   R visitAsyncForIn(AsyncForIn node) => visitForIn(node);
   R visitAsyncModifier(AsyncModifier node) => visitNode(node);
   R visitAwait(Await node) => visitExpression(node);
@@ skipping 1490 matching lines @@
   final Token beginToken;
   final Token endToken;
 
   Return(this.beginToken, this.endToken, this.expression);
 
   Return asReturn() => this;
 
   bool get hasExpression => expression != null;
 
   /// `true` if this return is of the form `=> e;`.
-  bool get isArrowBody => beginToken.info == Precedence.FUNCTION_INFO;
+  bool get isArrowBody => beginToken.info == TokenType.FUNCTION;
 
   accept(Visitor visitor) => visitor.visitReturn(this);
 
   accept1(Visitor1 visitor, arg) => visitor.visitReturn(this, arg);
 
   visitChildren(Visitor visitor) {
     if (expression != null) expression.accept(visitor);
   }
 
   visitChildren1(Visitor1 visitor, arg) {
@@ skipping 1737 matching lines @@
  */
 Object getTreeElement(TreeElementMixin node) => node._element;
 
 /**
  * Do not call this method directly.  Instead, use an instance of
  * TreeElements.
  */
 void setTreeElement(TreeElementMixin node, Object value) {
   node._element = value;
 }