Perform deep copy of NavigationItems for serialization.

ios/web/navigation/crw_session_controller.mm

 // Copyright 2012 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/crw_session_controller.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/format_macros.h"
@@ skipping 257 matching lines @@
   copy->_propertyReleaser_CRWSessionController.Init(
       copy, [CRWSessionController class]);
   copy->_tabId = [_tabId copy];
   copy->_openerId = [_openerId copy];
   copy->_openedByDOM = _openedByDOM;
   copy->_openerNavigationIndex = _openerNavigationIndex;
   copy.windowName = self.windowName;
   copy->_currentNavigationIndex = _currentNavigationIndex;
   copy->_previousNavigationIndex = _previousNavigationIndex;
   copy->_lastVisitedTimestamp = _lastVisitedTimestamp;
-  copy->_entries = [_entries copy];
+  copy->_entries =
+      [[NSMutableArray alloc] initWithArray:_entries copyItems:YES];
   copy->_sessionCertificatePolicyManager =
       [_sessionCertificatePolicyManager copy];
   copy->_xCallbackParameters = [_xCallbackParameters copy];
   return copy;
 }
 
 - (void)setCurrentNavigationIndex:(NSInteger)currentNavigationIndex {
   if (_currentNavigationIndex != currentNavigationIndex) {
     _currentNavigationIndex = currentNavigationIndex;
     if (_navigationManager)
@@ skipping 601 matching lines @@
   item->SetURL(loaded_url);
   item->SetReferrer(referrer);
   item->SetTransitionType(transition);
   item->SetIsOverridingUserAgent(useDesktopUserAgent);
   item->set_is_renderer_initiated(rendererInitiated);
   return [
       [[CRWSessionEntry alloc] initWithNavigationItem:item.Pass()] autorelease];
 }
 
 @end