[regexp] implement case-insensitive unicode regexps.

src/regexp/regexp-ast.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_AST_H_
 #define V8_REGEXP_REGEXP_AST_H_
 
 #include "src/objects.h"
 #include "src/utils.h"
 #include "src/zone.h"
@@ skipping 275 matching lines @@
 class RegExpCharacterClass final : public RegExpTree {
  public:
   RegExpCharacterClass(ZoneList<CharacterRange>* ranges, bool is_negated)
       : set_(ranges), is_negated_(is_negated) {}
   explicit RegExpCharacterClass(uc16 type) : set_(type), is_negated_(false) {}
   void* Accept(RegExpVisitor* visitor, void* data) override;
   RegExpNode* ToNode(RegExpCompiler* compiler, RegExpNode* on_success) override;
   RegExpCharacterClass* AsCharacterClass() override;
   bool IsCharacterClass() override;
   bool IsTextElement() override { return true; }
-  bool NeedsDesugaringForUnicode(Zone* zone);
   int min_match() override { return 1; }
   int max_match() override { return 1; }
   void AppendToText(RegExpText* text, Zone* zone) override;
   CharacterSet character_set() { return set_; }
   // TODO(lrn): Remove need for complex version if is_standard that
   // recognizes a mangled standard set and just do { return set_.is_special(); }
   bool is_standard(Zone* zone);
   // Returns a value representing the standard character set if is_standard()
   // returns true.
   // Currently used values are:
@@ skipping 203 matching lines @@
   RegExpEmpty* AsEmpty() override;
   bool IsEmpty() override;
   int min_match() override { return 0; }
   int max_match() override { return 0; }
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_REGEXP_REGEXP_AST_H_