add DCHECK that a server redirect pending item should never be added.

ios/web/navigation/navigation_manager_impl_unittest.mm

 // Copyright 2014 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/web/navigation/navigation_manager_impl.h"
 
 #include "base/logging.h"
 #import "base/mac/scoped_nsobject.h"
 #import "ios/web/navigation/crw_session_controller+private_constructors.h"
 #import "ios/web/navigation/navigation_manager_delegate.h"
@@ skipping 236 matching lines @@
 // Tests CanGoToOffset API for positive, negative and zero delta. Tested
 // navigation manager will have redirect entries to make sure they are
 // appropriately skipped.
 TEST_F(NavigationManagerTest, OffsetsWithoutPendingIndex) {
   navigation_manager()->AddPendingItem(
       GURL("http://www.url.com/0"), Referrer(), ui::PAGE_TRANSITION_LINK,
       web::NavigationInitiationType::USER_INITIATED);
   [session_controller() commitPendingItem];
   navigation_manager()->AddPendingItem(
       GURL("http://www.url.com/redirect"), Referrer(),
-      ui::PAGE_TRANSITION_IS_REDIRECT_MASK,
+      ui::PAGE_TRANSITION_CLIENT_REDIRECT,
       web::NavigationInitiationType::USER_INITIATED);
   [session_controller() commitPendingItem];
   navigation_manager()->AddPendingItem(
       GURL("http://www.url.com/1"), Referrer(), ui::PAGE_TRANSITION_LINK,
       web::NavigationInitiationType::USER_INITIATED);
   [session_controller() commitPendingItem];
   navigation_manager()->AddPendingItem(
       GURL("http://www.url.com/2"), Referrer(), ui::PAGE_TRANSITION_LINK,
       web::NavigationInitiationType::USER_INITIATED);
   [session_controller() commitPendingItem];
   navigation_manager()->AddPendingItem(
       GURL("http://www.url.com/redirect"), Referrer(),
-      ui::PAGE_TRANSITION_IS_REDIRECT_MASK,
+      ui::PAGE_TRANSITION_CLIENT_REDIRECT,
       web::NavigationInitiationType::USER_INITIATED);
   [session_controller() commitPendingItem];
   ASSERT_EQ(5, navigation_manager()->GetItemCount());
   ASSERT_EQ(4, navigation_manager()->GetLastCommittedItemIndex());
 
   // Go to entry at index 1 and test API from that state.
   [session_controller() goToItemAtIndex:1];
   ASSERT_EQ(1, navigation_manager()->GetLastCommittedItemIndex());
   ASSERT_EQ(-1, navigation_manager()->GetPendingItemIndex());
   EXPECT_FALSE(navigation_manager()->CanGoToOffset(-1));
@@ skipping 327 matching lines @@
 
   GURL url_before_reload = navigation_manager()->GetVisibleItem()->GetURL();
   navigation_manager()->Reload(web::ReloadType::NORMAL,
                                false /* check_for_repost */);
 
   EXPECT_EQ(url_before_reload,
             navigation_manager()->GetVisibleItem()->GetURL());
 }
 
 }  // namespace web