[esnext] implement frontend changes for async/await proposal

src/parsing/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_PARSING_SCANNER_H_
 #define V8_PARSING_SCANNER_H_
 
 #include "src/allocation.h"
@@ skipping 424 matching lines @@
   // tokens, which is what it is used for.
   void SeekForward(int pos);
 
   // Returns true if there was a line terminator before the peek'ed token,
   // possibly inside a multi-line comment.
   bool HasAnyLineTerminatorBeforeNext() const {
     return has_line_terminator_before_next_ ||
            has_multiline_comment_before_next_;
   }
 
+  bool HasAnyLineTerminatorAfterNext() {
+    Token::Value ensure_next_next = PeekAhead();
+    USE(ensure_next_next);
+    return has_line_terminator_after_next_;
+  }
+
   // Scans the input as a regular expression pattern, previous
   // character(s) must be /(=). Returns true if a pattern is scanned.
   bool ScanRegExpPattern(bool seen_equal);
   // Scans the input as regular expression flags. Returns the flags on success.
   Maybe<RegExp::Flags> ScanRegExpFlags();
 
   // Scans the input as a template literal
   Token::Value ScanTemplateStart();
   Token::Value ScanTemplateContinuation();
 
@@ skipping 324 matching lines @@
   // One Unicode character look-ahead; c0_ < 0 at the end of the input.
   uc32 c0_;
 
   // Whether there is a line terminator whitespace character after
   // the current token, and  before the next. Does not count newlines
   // inside multiline comments.
   bool has_line_terminator_before_next_;
   // Whether there is a multi-line comment that contains a
   // line-terminator after the current token, and before the next.
   bool has_multiline_comment_before_next_;
+  bool has_line_terminator_after_next_;
 
   // Whether this scanner encountered an HTML comment.
   bool found_html_comment_;
 
   bool allow_harmony_exponentiation_operator_;
 
   MessageTemplate::Template scanner_error_;
   Location scanner_error_location_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_PARSING_SCANNER_H_