Implement and test CanonicalCookie::IsCanonical()

ios/net/cookies/cookie_store_ios_persistent_unittest.mm

Index: ios/net/cookies/cookie_store_ios_persistent_unittest.mm
diff --git a/ios/net/cookies/cookie_store_ios_persistent_unittest.mm b/ios/net/cookies/cookie_store_ios_persistent_unittest.mm
index 1a412110dea12fe62dcf9e603d6be43433c38271..85706f608f672c4aece73605fe1aa677c8c43198 100644
--- a/ios/net/cookies/cookie_store_ios_persistent_unittest.mm
+++ b/ios/net/cookies/cookie_store_ios_persistent_unittest.mm
@@ -30,6 +30,7 @@ struct InactiveCookieStoreIOSTestTraits {
   static const bool preserves_trailing_dots = true;
   static const bool filters_schemes = false;
   static const bool has_path_prefix_bug = false;
+  static const bool forbids_setting_empty_name = false;
   static const int creation_time_granularity_in_ms = 0;
   static const int enforces_prefixes = true;
   static const bool enforce_strict_secure = false;
@@ -125,4 +126,4 @@ TEST_F(CookieStoreIOSPersistentTest, NotSynchronized) {
   EXPECT_EQ("a=b", callback.cookie_line());
 }
 
-}  // namespace net
+}  // namespace net