Added WebStateImpl::OnNavigationFinished().

ios/web/web_state/web_state_impl.mm

Index: ios/web/web_state/web_state_impl.mm
diff --git a/ios/web/web_state/web_state_impl.mm b/ios/web/web_state/web_state_impl.mm
index b5a047dccfdfc0b54760ee71daacc47564f3f2ee..acd420c138e5f802766d70d2a6bbd6a8d0aeab17 100644
--- a/ios/web/web_state/web_state_impl.mm
+++ b/ios/web/web_state/web_state_impl.mm
@@ -698,6 +698,11 @@ void WebStateImpl::OnProvisionalNavigationStarted(const GURL& url) {
     observer.ProvisionalNavigationStarted(url);
 }
 
+void WebStateImpl::OnNavigationFinished(web::NavigationContext* context) {
+  for (auto& observer : observers_)
+    observer.DidFinishNavigation(context);
+}
+
 #pragma mark - NavigationManagerDelegate implementation
 
 void WebStateImpl::GoToIndex(int index) {