Revert "Updated ownership of NavigationItems within CRWSessionController."

ios/web/navigation/crw_session_controller.h

Index: ios/web/navigation/crw_session_controller.h
diff --git a/ios/web/navigation/crw_session_controller.h b/ios/web/navigation/crw_session_controller.h
index 5f9c149af89007501c8443740948b74fc7c9ade5..3859af2ac855ff9e46ca38356c75d34b536b6584 100644
--- a/ios/web/navigation/crw_session_controller.h
+++ b/ios/web/navigation/crw_session_controller.h
@@ -8,7 +8,7 @@
 #import <Foundation/Foundation.h>
 #include <vector>
 
-#import "ios/web/navigation/navigation_item_impl_list.h"
+#include "ios/web/public/navigation_item_list.h"
 #include "ui/base/page_transition_types.h"
 #include "url/gurl.h"
 
@@ -46,9 +46,8 @@ struct Referrer;
 @property(nonatomic, readonly, copy) NSString* openerId;
 @property(nonatomic, readonly, assign) NSInteger openerNavigationIndex;
 
-// The ScopedNavigationItemImplList used to store the NavigationItemImpls for
-// this session.
-@property(nonatomic, readonly) const web::ScopedNavigationItemImplList& items;
+// The list of CRWSessionEntries in |_entries|'s NavigationItemImpls.
+@property(nonatomic, readonly) web::NavigationItemList items;
 // The current NavigationItem.  During a pending navigation, returns the
 // NavigationItem for that navigation.  If a transient NavigationItem exists,
 // this NavigationItem will be returned.
@@ -137,7 +136,8 @@ struct Referrer;
 - (void)discardNonCommittedItems;
 
 // Inserts history state from |otherController| to the front of |items|.  This
-// function will create copies of |otherController|'s NavigationItems.
+// function transfers ownership of |otherController|'s NavigationItems to the
+// receiver.
 - (void)insertStateFromSessionController:(CRWSessionController*)otherController;
 
 // Sets |currentNavigationIndex_| to the |index| if it's in the entries bounds.