[parser] Refactor some CHECK_OK calls

src/parsing/parser.h

 // 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.
 
 #ifndef V8_PARSING_PARSER_H_
 #define V8_PARSING_PARSER_H_
 
 #include "src/allocation.h"
 #include "src/ast/ast.h"
 #include "src/ast/scopes.h"
@@ skipping 457 matching lines @@
                        ParseErrorType error_type = kSyntaxError);
   void ReportMessage(MessageTemplate::Template message, const char* arg = NULL,
                      ParseErrorType error_type = kSyntaxError);
   void ReportMessage(MessageTemplate::Template message, const AstRawString* arg,
                      ParseErrorType error_type = kSyntaxError);
   void ReportMessageAt(Scanner::Location source_location,
                        MessageTemplate::Template message,
                        const AstRawString* arg,
                        ParseErrorType error_type = kSyntaxError);
 
+  // A dummy function, just useful as an argument to CHECK_OK_CUSTOM.
+  static void Void() {}
+
   // "null" return type creators.
   static const AstRawString* EmptyIdentifier() {
     return NULL;
   }
   static Expression* EmptyExpression() {
     return NULL;
   }
   static Literal* EmptyLiteral() {
     return NULL;
   }
@@ skipping 823 matching lines @@
 
 DoExpression* ParserTraits::ParseDoExpression(bool* ok) {
   return parser_->ParseDoExpression(ok);
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_PARSER_H_