Fix ??= AST modification

runtime/vm/parser.h

 // 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.
 
 #ifndef VM_PARSER_H_
 #define VM_PARSER_H_
 
 #include "include/dart_api.h"
 
 #include "platform/assert.h"
@@ skipping 782 matching lines @@
 
   void SetupSavedTryContext(LocalVariable* saved_try_context);
 
   void CheckOperatorArity(const MemberDesc& member);
 
   void EnsureExpressionTemp();
   bool IsLegalAssignableSyntax(AstNode* expr, intptr_t end_pos);
   AstNode* CreateAssignmentNode(AstNode* original,
                                 AstNode* rhs,
                                 const String* left_ident,
-                                intptr_t left_pos);
+                                intptr_t left_pos,
+                                bool is_compound = false);
   AstNode* InsertClosureCallNodes(AstNode* condition);
 
   ConstructorCallNode* CreateConstructorCallNode(
       intptr_t token_pos,
       const TypeArguments& type_arguments,
       const Function& constructor,
       ArgumentListNode* arguments);
 
   void AddEqualityNullCheck();
 
@@ skipping 67 matching lines @@
 
   // Indentation of parser trace.
   intptr_t trace_indent_;
 
   DISALLOW_COPY_AND_ASSIGN(Parser);
 };
 
 }  // namespace dart
 
 #endif  // VM_PARSER_H_