Make multi-line comments not count when checking whether --> is first on a line.

src/scanner-base.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 461 matching lines @@
   explicit JavaScriptScanner(UnicodeCache* scanner_contants);
 
   // Returns the next token.
   Token::Value Next();
 
   // Returns true if there was a line terminator before the peek'ed token.
   bool has_line_terminator_before_next() const {
     return has_line_terminator_before_next_;
   }
 
+  // Returns true if there was no non-whitespace on the line before the
+  // peek'ed token.
+  bool next_is_first_on_line() const {
+    return next_is_first_on_line_;
+  }
+
   // 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);
   // Returns true if regexp flags are scanned (always since flags can
   // be empty).
   bool ScanRegExpFlags();
 
   // Tells whether the buffer contains an identifier (no escapes).
   // Used for checking if a property name is an identifier.
   static bool IsIdentifier(unibrow::CharacterStream* buffer);
@@ skipping 30 matching lines @@
   // Scans a possible HTML comment -- begins with '<!'.
   Token::Value ScanHtmlComment();
 
   // Decodes a unicode escape-sequence which is part of an identifier.
   // If the escape sequence cannot be decoded the result is kBadChar.
   uc32 ScanIdentifierUnicodeEscape();
 
   // Start position of the octal literal last scanned.
   Location octal_pos_;
 
+  // Whether there is a line terminator between the current proper
+  // token and the next one (ignoring whitespace tokens and comments).
   bool has_line_terminator_before_next_;
+  // Whether there is only whitespace (and not comments) on the current
+  // line until now.
+  bool next_is_first_on_line_;
 };
 
 
 // ----------------------------------------------------------------------------
 // Keyword matching state machine.
 
 class KeywordMatcher {
 //  Incrementally recognize keywords.
 //
 //  Recognized keywords:
@@ skipping 118 matching lines @@
   // keyword with the current prefix).
   const char* keyword_;
   int counter_;
   Token::Value keyword_token_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_SCANNER_BASE_H_