Ignore cookies with invalid 'SameSite' attribute values.

net/cookies/parsed_cookie.h

Index: net/cookies/parsed_cookie.h
diff --git a/net/cookies/parsed_cookie.h b/net/cookies/parsed_cookie.h
index ebb14de7812bd59379c4cf823f2a192fad245cc0..f48015dbd2f56ed0d18dc5c2b4cedaba65c658e8 100644
--- a/net/cookies/parsed_cookie.h
+++ b/net/cookies/parsed_cookie.h
@@ -129,6 +129,10 @@ class NET_EXPORT ParsedCookie {
   // |index| refers to a position in |pairs_|.
   void ClearAttributePair(size_t index);
 
+  // Returns false if a 'SameSite' attribute is present, but has an unrecognized
+  // value. In particular, this includes attributes with empty values.
+  bool IsSameSiteAttributeValid() const;
+
   PairList pairs_;
   // These will default to 0, but that should never be valid since the
   // 0th index is the user supplied token/value, not an attribute.