net: make CanonicalCookie's constructor private

ios/net/cookies/system_cookie_util_unittest.mm

Index: ios/net/cookies/system_cookie_util_unittest.mm
diff --git a/ios/net/cookies/system_cookie_util_unittest.mm b/ios/net/cookies/system_cookie_util_unittest.mm
index ddca58306cbbf85f099075e314be8b7dfef64b8a..87a573c69962167f56f3f28812480319d36d5e0d 100644
--- a/ios/net/cookies/system_cookie_util_unittest.mm
+++ b/ios/net/cookies/system_cookie_util_unittest.mm
@@ -26,8 +26,8 @@ const char kCookieValueInvalidUtf8[] = "\x81r\xe4\xbd\xa0\xe5\xa5\xbd";
 
 void CheckSystemCookie(const base::Time& expires, bool secure, bool httponly) {
   // Generate a canonical cookie.
-  net::CanonicalCookie canonical_cookie = net::CanonicalCookie(
-      GURL(), kCookieName, kCookieValue, kCookieDomain, kCookiePath,
+  net::CanonicalCookie canonical_cookie = *net::CanonicalCookie::Create(
+      kCookieName, kCookieValue, kCookieDomain, kCookiePath,
       base::Time(),  // creation
       expires,
       base::Time(),  // last_access
@@ -116,8 +116,8 @@ TEST(CookieUtil, SystemCookieFromCanonicalCookie) {
 
 TEST(CookieUtil, SystemCookieFromBadCanonicalCookie) {
   // Generate a bad canonical cookie (value is invalid utf8).
-  net::CanonicalCookie bad_canonical_cookie = net::CanonicalCookie(
-      GURL(), kCookieName, kCookieValueInvalidUtf8, kCookieDomain, kCookiePath,
+  net::CanonicalCookie bad_canonical_cookie = *net::CanonicalCookie::Create(
+      kCookieName, kCookieValueInvalidUtf8, kCookieDomain, kCookiePath,
       base::Time(),  // creation
       base::Time(),  // expires
       base::Time(),  // last_access