[ios] Removed remaining code for URL spoofing interstitials.

ios/public/provider/chrome/browser/browser_constants.cc

Index: ios/public/provider/chrome/browser/browser_constants.cc
diff --git a/ios/public/provider/chrome/browser/browser_constants.cc b/ios/public/provider/chrome/browser/browser_constants.cc
deleted file mode 100644
index 5b89c12eb042b19543f7c5f2532ae8d0a7fe7fe1..0000000000000000000000000000000000000000
--- a/ios/public/provider/chrome/browser/browser_constants.cc
+++ /dev/null
@@ -1,11 +0,0 @@
-// Copyright 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "ios/public/provider/chrome/browser/browser_constants.h"
-
-namespace ios {
-
-const char kSpoofingAttemptFlag[] = "SpoofingAttempt_IOS";
-
-}  // namespace ios