[parser] Treat \ufffe as non-whitespace.

R=marja@chromium.org

Bug: chromium:726625
Change-Id: I3f451a47b5a60a4c367d04a5466acd9e2f90df14
Reviewed-on: https://chromium-review.googlesource.com/530849Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Daniel Vogelheim <vogelheim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46063}

src/parsing/scanner.cc

@@ -429,18 +429,6 @@ Token::Value Scanner::PeekAhead() {
 }
 
 
-// TODO(yangguo): check whether this is actually necessary.
-static inline bool IsLittleEndianByteOrderMark(uc32 c) {
-  // The Unicode value U+FFFE is guaranteed never to be assigned as a
-  // Unicode character; this implies that in a Unicode context the
-  // 0xFF, 0xFE byte pattern can only be interpreted as the U+FEFF
-  // character expressed in little-endian byte order (since it could
-  // not be a U+FFFE character expressed in big-endian byte
-  // order). Nevertheless, we check for it to be compatible with
-  // Spidermonkey.
-  return c == 0xFFFE;
-}
-
 Token::Value Scanner::SkipWhiteSpace() {
   int start_position = source_pos();
 
@@ -453,8 +441,7 @@ Token::Value Scanner::SkipWhiteSpace() {
       // Remember if the latter is the case.
       if (unicode_cache_->IsLineTerminator(c0_)) {
         has_line_terminator_before_next_ = true;
-      } else if (!unicode_cache_->IsWhiteSpace(c0_) &&
-                 !IsLittleEndianByteOrderMark(c0_)) {
+      } else if (!unicode_cache_->IsWhiteSpace(c0_)) {
         break;
       }
       Advance();

test/mjsunit/regress/regress-726625.js

+// Copyright 2017 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.
+
+function abc() { return; }
+assertThrows("abc" + String.fromCharCode(65534) + "(1)");

test/mozilla/mozilla.status

@@ -115,6 +115,9 @@
   # Function declarations are no longer allowed as the body of a with statement.
   'js1_5/Regress/regress-326453': [FAIL],
 
+  # Invalid according to ES2015 syntax. (Details: crbug.com/726625)
+  'ecma_3/extensions/regress-368516': [FAIL],
+
   ##################### SKIPPED TESTS #####################
 
   # This test checks that we behave properly in an out-of-memory