Revert of [regexp] restrict pattern syntax for unicode mode.

src/regexp/regexp-parser.h

 // Copyright 2016 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_REGEXP_REGEXP_PARSER_H_
 #define V8_REGEXP_REGEXP_PARSER_H_
 
 #include "src/objects.h"
 #include "src/regexp/regexp-ast.h"
 #include "src/zone.h"
@@ skipping 93 matching lines @@
   void AddUnicodeCharacter(uc32 character);
   // "Adds" an empty expression. Does nothing except consume a
   // following quantifier
   void AddEmpty();
   void AddCharacterClass(RegExpCharacterClass* cc);
   void AddCharacterClassForDesugaring(uc32 c);
   void AddAtom(RegExpTree* tree);
   void AddTerm(RegExpTree* tree);
   void AddAssertion(RegExpTree* tree);
   void NewAlternative();  // '|'
-  bool AddQuantifierToAtom(int min, int max,
+  void AddQuantifierToAtom(int min, int max,
                            RegExpQuantifier::QuantifierType type);
   RegExpTree* ToRegExp();
 
  private:
   static const uc16 kNoPendingSurrogate = 0;
   void AddLeadSurrogate(uc16 lead_surrogate);
   void AddTrailSurrogate(uc16 trail_surrogate);
   void FlushPendingSurrogate();
   void FlushCharacters();
   void FlushText();
@@ skipping 66 matching lines @@
   // Only use if the result of the parse is a single atom node.
   bool simple();
   bool contains_anchor() { return contains_anchor_; }
   void set_contains_anchor() { contains_anchor_ = true; }
   int captures_started() { return captures_started_; }
   int position() { return next_pos_ - 1; }
   bool failed() { return failed_; }
   bool unicode() const { return (flags_ & JSRegExp::kUnicode) != 0; }
   bool multiline() const { return (flags_ & JSRegExp::kMultiline) != 0; }
 
-  static bool IsSyntaxCharacterOrSlash(uc32 c);
+  static bool IsSyntaxCharacter(uc32 c);
 
   static const int kMaxCaptures = 1 << 16;
   static const uc32 kEndMarker = (1 << 21);
 
  private:
   enum SubexpressionType {
     INITIAL,
     CAPTURE,  // All positive values represent captures.
     POSITIVE_LOOKAROUND,
     NEGATIVE_LOOKAROUND,
@@ skipping 72 matching lines @@
   bool simple_;
   bool contains_anchor_;
   bool is_scanned_for_captures_;
   bool failed_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_REGEXP_REGEXP_PARSER_H_