Separate DuplicateFinder from Scanner.

src/parsing/expression-classifier.h

 // Copyright 2015 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_EXPRESSION_CLASSIFIER_H
 #define V8_PARSING_EXPRESSION_CLASSIFIER_H
 
 #include "src/messages.h"
 #include "src/parsing/scanner.h"
 #include "src/parsing/token.h"
 
 namespace v8 {
 namespace internal {
 
+class DuplicateFinder;
+
 #define ERROR_CODES(T)                       \
   T(ExpressionProduction, 0)                 \
   T(FormalParameterInitializerProduction, 1) \
   T(BindingPatternProduction, 2)             \
   T(AssignmentPatternProduction, 3)          \
   T(DistinctFormalParametersProduction, 4)   \
   T(StrictModeFormalParametersProduction, 5) \
   T(ArrowFormalParametersProduction, 6)      \
   T(LetPatternProduction, 7)                 \
   T(ObjectLiteralProduction, 8)              \
@@ skipping 434 matching lines @@
 };
 
 
 #undef ERROR_CODES
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_EXPRESSION_CLASSIFIER_H