[parser] Lift template literal invalid escape restriction

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/ast/ast.h"
 #include "src/ast/scopes.h"
 #include "src/base/compiler-specific.h"
@@ skipping 568 matching lines @@
    private:
     ZoneList<Expression*> cooked_;
     ZoneList<Expression*> raw_;
     ZoneList<Expression*> expressions_;
     int pos_;
   };
 
   typedef TemplateLiteral* TemplateLiteralState;
 
   TemplateLiteralState OpenTemplateLiteral(int pos);
-  void AddTemplateSpan(TemplateLiteralState* state, bool tail);
+  // "should_cook" means that the span can be "cooked": in tagged template
+  // literals, both the raw and "cooked" representations are available to user
+  // code ("cooked" meaning that escape sequences are converted to their
+  // interpreted values). With the --harmony-template-escapes flag, invalid
+  // escape sequences cause the cooked span to be represented by undefined,
+  // instead of being a syntax error.
+  // "tail" indicates that this span is the last in the literal.
+  void AddTemplateSpan(TemplateLiteralState* state, bool should_cook,
+                       bool tail);
   void AddTemplateExpression(TemplateLiteralState* state,
                              Expression* expression);
   Expression* CloseTemplateLiteral(TemplateLiteralState* state, int start,
                                    Expression* tag);
   uint32_t ComputeTemplateLiteralHash(const TemplateLiteral* lit);
 
   ZoneList<Expression*>* PrepareSpreadArguments(ZoneList<Expression*>* list);
   Expression* SpreadCall(Expression* function, ZoneList<Expression*>* args,
                          int pos, Call::PossiblyEval is_possibly_eval);
   Expression* SpreadCallNew(Expression* function, ZoneList<Expression*>* args,
@@ skipping 578 matching lines @@
 
  private:
   ParserTarget** variable_;
   ParserTarget* previous_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_PARSER_H_