Implement the new '?.' operator in analyzer.

pkg/analyzer/lib/src/generated/testing/ast_factory.dart

 // Copyright (c) 2014, 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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.testing.ast_factory;
 
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 604 matching lines @@
       TypeName returnType, Keyword property, Keyword operator,
       SimpleIdentifier name, FormalParameterList parameters,
       FunctionBody body) => new MethodDeclaration(null, null, null,
       modifier == null ? null : TokenFactory.tokenFromKeyword(modifier),
       returnType,
       property == null ? null : TokenFactory.tokenFromKeyword(property),
       operator == null ? null : TokenFactory.tokenFromKeyword(operator), name,
       parameters, body);
 
   static MethodInvocation methodInvocation(Expression target, String methodName,
-      [List<Expression> arguments]) => new MethodInvocation(target,
-      target == null ? null : TokenFactory.tokenFromType(TokenType.PERIOD),
+      [List<Expression> arguments,
+      TokenType operator = TokenType.PERIOD]) => new MethodInvocation(target,
+      target == null ? null : TokenFactory.tokenFromType(operator),
       identifier3(methodName), argumentList(arguments));
 
   static MethodInvocation methodInvocation2(String methodName,
           [List<Expression> arguments]) =>
       methodInvocation(null, methodName, arguments);
 
   static NamedExpression namedExpression(Label label, Expression expression) =>
       new NamedExpression(label, expression);
 
   static NamedExpression namedExpression2(
@@ skipping 306 matching lines @@
       new YieldStatement(
           TokenFactory.tokenFromTypeAndString(TokenType.IDENTIFIER, "yield"),
           TokenFactory.tokenFromType(TokenType.STAR), expression,
           TokenFactory.tokenFromType(TokenType.SEMICOLON));
 
   static YieldStatement yieldStatement(
       Expression expression) => new YieldStatement(
       TokenFactory.tokenFromTypeAndString(TokenType.IDENTIFIER, "yield"), null,
       expression, TokenFactory.tokenFromType(TokenType.SEMICOLON));
 }