Use DidFinishNavigation callback in LanguageDetectionController.

ios/web/web_state/ui/crw_web_controller.mm

Index: ios/web/web_state/ui/crw_web_controller.mm
diff --git a/ios/web/web_state/ui/crw_web_controller.mm b/ios/web/web_state/ui/crw_web_controller.mm
index 6d0fb2cfa2b052059efebef06219a0dee45a6672..333a0d68c8e9d5f49dce8b82604e55afd74d28f6 100644
--- a/ios/web/web_state/ui/crw_web_controller.mm
+++ b/ios/web/web_state/ui/crw_web_controller.mm
@@ -2862,8 +2862,6 @@ const NSTimeInterval kSnapshotOverlayTransition = 0.5;
     item->SetIsCreatedFromHashChange(true);
   }
 
-  // Notify the observers.
-  _webStateImpl->OnUrlHashChanged();
   return YES;
 }
 
@@ -2962,8 +2960,6 @@ const NSTimeInterval kSnapshotOverlayTransition = 0.5;
       return;
     base::scoped_nsobject<CRWWebController> strongSelf([weakSelf retain]);
     [strongSelf optOutScrollsToTopForSubviews];
-    // Notify the observers.
-    strongSelf.get()->_webStateImpl->OnHistoryStateChanged();
     [strongSelf didFinishNavigation];
   }];
   return YES;