Adds NavigationManager util functions to ios/chrome/browser/web/

ios/chrome/browser/web/navigation_manager_util.mm

+// Copyright 2017 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.
+
+#import "ios/chrome/browser/web/navigation_manager_util.h"
+
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
+web::NavigationItem* GetLastNonRedirectedItem(
+    web::NavigationManager* nav_manager) {
+  if (!nav_manager->GetItemCount())
+    return nullptr;
+  int index = nav_manager->GetCurrentItemIndex();
+  web::NavigationItem* item = nullptr;
+  while (index >= 0) {
+    item = nav_manager->GetItemAtIndex(index);
+    // Returns the first non-Redirect item found.
+    if ((item->GetTransitionType() & ui::PAGE_TRANSITION_IS_REDIRECT_MASK) == 0)
+      break;
+    --index;
+  }
+  return item;
+}