Merge V8 5.2.361.47  DO NOT MERGE

https://chromium.googlesource.com/v8/v8/+/5.2.361.47

FPIIM-449

Change-Id: Ibec421b85a9b88cb3a432ada642e469fe7e78346
(cherry picked from commit bcf72ee8e3b26f1d0726869c7ddb3921c68b09a8)
diff --git a/src/unicode-inl.h b/src/unicode-inl.h
index b22e482..ebebfaa 100644
--- a/src/unicode-inl.h
+++ b/src/unicode-inl.h
@@ -137,6 +137,12 @@
   }
 }
 
+bool Utf8::IsValidCharacter(uchar c) {
+  return c < 0xD800u || (c >= 0xE000u && c < 0xFDD0u) ||
+         (c > 0xFDEFu && c <= 0x10FFFFu && (c & 0xFFFEu) != 0xFFFEu &&
+          c != kBadChar);
+}
+
 }  // namespace unibrow
 
 #endif  // V8_UNICODE_INL_H_