Implement ES6 unicode escapes.

src/scanner.h

 // Copyright 2011 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.
 
 // Features shared by parsing and pre-parsing scanners.
 
 #ifndef V8_SCANNER_H_
 #define V8_SCANNER_H_
 
 #include "src/allocation.h"
@@ skipping 619 matching lines @@
 
   Token::Value ScanString();
 
   // Scans an escape-sequence which is part of a string and adds the
   // decoded character to the current literal. Returns true if a pattern
   // is scanned.
   bool ScanEscape();
   // Decodes a Unicode escape-sequence which is part of an identifier.
   // If the escape sequence cannot be decoded the result is kBadChar.
   uc32 ScanIdentifierUnicodeEscape();
+  // Helper for the above functions.
+  uc32 ScanUnicodeEscape();
 
   // Return the current source position.
   int source_pos() {
     return source_->pos() - kCharacterLookaheadBufferSize;
   }
 
   UnicodeCache* unicode_cache_;
 
   // Buffers collecting literal strings, numbers, etc.
   LiteralBuffer literal_buffer1_;
@@ skipping 29 matching lines @@
   bool harmony_modules_;
   // Whether we scan 0o777 and 0b111 as numbers.
   bool harmony_numeric_literals_;
   // Whether we scan 'class', 'extends', 'static' and 'super' as keywords.
   bool harmony_classes_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCANNER_H_