[parser] improve inferred function names for async arrow functions

src/parsing/parser.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/parsing/parser.h"
 
 #include <memory>
 
 #include "src/api.h"
 #include "src/ast/ast.h"
@@ skipping 748 matching lines @@
       return factory->NewNumberLiteral(value, pos, has_dot);
     }
     default:
       DCHECK(false);
   }
   return NULL;
 }
 
 Expression* ParserTraits::ExpressionFromIdentifier(const AstRawString* name,
                                                    int start_position,
-                                                   int end_position) {
-  if (parser_->fni_ != NULL) parser_->fni_->PushVariableName(name);
+                                                   int end_position,
+                                                   InferName infer) {
+  if (infer == InferName::Yes && parser_->fni_ != NULL) {
+    parser_->fni_->PushVariableName(name);
+  }
   return parser_->NewUnresolved(name, start_position, end_position);
 }
 
 
 Expression* ParserTraits::ExpressionFromString(int pos, Scanner* scanner,
                                                AstNodeFactory* factory) {
   const AstRawString* symbol = GetSymbol(scanner);
   if (parser_->fni_ != NULL) parser_->fni_->PushLiteralName(symbol);
   return factory->NewStringLiteral(symbol, pos);
 }
@@ skipping 6289 matching lines @@
   node->Print(Isolate::Current());
 }
 #endif  // DEBUG
 
 #undef CHECK_OK
 #undef CHECK_OK_VOID
 #undef CHECK_FAILED
 
 }  // namespace internal
 }  // namespace v8