Implemented WebStateObserver::DidFinishNavigation(NavigationHandle*).

ios/web/web_state/web_state_impl.h

Index: ios/web/web_state/web_state_impl.h
diff --git a/ios/web/web_state/web_state_impl.h b/ios/web/web_state/web_state_impl.h
index a9469900f2c1afe142e04037bfdf8f12b5092dab..4b7754ae69ad58cd33451082f61d7507576881a6 100644
--- a/ios/web/web_state/web_state_impl.h
+++ b/ios/web/web_state/web_state_impl.h
@@ -88,6 +88,12 @@ class WebStateImpl : public WebState, public NavigationManagerDelegate {
   // Notifies the observers that the history state of the current page changed.
   void OnHistoryStateChanged();
 
+  // Notifies the observers that same page navigation did finish.
+  void OnSamePageNavigation(const GURL& url);
+
+  // Notifies the observers that navigation to error page did finish.
+  void OnErrorPageNavigation(const GURL& url);
+
   // Notifies the observers that the render process was terminated.
   void OnRenderProcessGone();