Track async state in parser.

pkg/analyzer/lib/src/summary/fasta/summary_builder.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.
 
 /// Logic to build unlinked summaries.
 library summary.src.summary_builder;
 
 import 'package:front_end/src/fasta/parser/class_member_parser.dart';
 import 'package:front_end/src/fasta/parser/identifier_context.dart';
 import 'package:front_end/src/fasta/parser/parser.dart';
@@ skipping 80 matching lines @@
   return listener.topScope.unit;
 }
 
 /// Builder for constant expressions.
 ///
 /// Any invalid subexpression is denoted with [Invalid].
 class ConstExpressionBuilder extends ExpressionListener {
   final Uri uri;
   Parser parser;
   ConstExpressionBuilder(this.uri) {
-    parser = new Parser(this, asyncAwaitKeywordsEnabled: true);
+    parser = new Parser(this);
   }
   bool get forConst => true;
 
   void endArguments(int count, Token begin, Token end) {
     debugEvent("Arguments");
     if (ignore) return;
     push(popList(count) ?? const []);
   }
 
   void handleAsOperator(Token op, Token next) {
@@ skipping 491 matching lines @@
 
 /// Builder for initializer expressions. These expressions exclude any nested
 /// expression that is not needed to infer strong mode types.
 class InitializerBuilder extends ExpressionListener {
   final Uri uri;
   Parser parser;
 
   int _inArguments = 0;
 
   InitializerBuilder(this.uri) {
-    parser = new Parser(this, asyncAwaitKeywordsEnabled: true);
+    parser = new Parser(this);
   }
 
   bool get ignore => super.ignore || _inArguments > 0;
 
   void beginArguments(Token token) {
     // TODO(sigmund): determine if we can ignore arguments.
     //_inArguments++;
   }
 
   // Not necessary, but we don't use the value, so we can abstract it:
@@ skipping 966 matching lines @@
 }
 
 /// Internal representation of an initialized name.
 class _InitializedName {
   final String name;
   final UnlinkedExecutableBuilder initializer;
   _InitializedName(this.name, this.initializer);
 
   toString() => "II:" + (initializer != null ? "$name = $initializer" : name);
 }