Created NavigationManager::CopyStateFromAndPrune().

ios/chrome/browser/ui/browser_view_controller.mm

Index: ios/chrome/browser/ui/browser_view_controller.mm
diff --git a/ios/chrome/browser/ui/browser_view_controller.mm b/ios/chrome/browser/ui/browser_view_controller.mm
index 6a4a6377932b8bb80bc74322b25a863d130bcf91..59a76ae81321b5afa2632fe4593f5a8bdbe20aed 100644
--- a/ios/chrome/browser/ui/browser_view_controller.mm
+++ b/ios/chrome/browser/ui/browser_view_controller.mm
@@ -3678,15 +3678,12 @@ - (void)loadURL:(const GURL&)url
     Tab* newTab = [_preloadController releasePrerenderContents];
     DCHECK(oldTab);
     DCHECK(newTab);
-    if (oldTab && newTab) {
+    bool canPruneItems =
+        [newTab navigationManager]->CanPruneAllButLastCommittedItem();
+    if (oldTab && newTab && canPruneItems) {
       [oldTab recordStateInHistory];
-      DCHECK([newTab navigationManager]);
-      CRWSessionController* newHistory =
-          [newTab navigationManagerImpl]->GetSessionController();
-      DCHECK([oldTab navigationManager]);
-      CRWSessionController* oldHistory =
-          [oldTab navigationManagerImpl]->GetSessionController();
-      [newHistory insertStateFromSessionController:oldHistory];
+      [newTab navigationManager]->CopyStateFromAndPrune(
+          [oldTab navigationManager]);
       [[newTab nativeAppNavigationController]
           copyStateFrom:[oldTab nativeAppNavigationController]];
       [_model replaceTab:oldTab withTab:newTab];