[Navigation Experiment] Add WKBasedNavigationManagerImpl.

ios/web/test/fakes/test_navigation_manager_delegate.mm

Index: ios/web/test/fakes/test_navigation_manager_delegate.mm
diff --git a/ios/web/test/fakes/test_navigation_manager_delegate.mm b/ios/web/test/fakes/test_navigation_manager_delegate.mm
index 7f480b3b9cb198bf38edb6690d60fd7347d9b91c..85a064ff8d6f582825889f2d171655b38d03c032 100644
--- a/ios/web/test/fakes/test_navigation_manager_delegate.mm
+++ b/ios/web/test/fakes/test_navigation_manager_delegate.mm
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #import "ios/web/test/fakes/test_navigation_manager_delegate.h"
+#import "ios/web/web_state/ui/crw_web_view_navigation_proxy.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
@@ -22,5 +23,9 @@ void TestNavigationManagerDelegate::OnNavigationItemCommitted(
 WebState* TestNavigationManagerDelegate::GetWebState() {
   return nullptr;
 }
+id<CRWWebViewNavigationProxy>
+TestNavigationManagerDelegate::GetWebViewNavigationProxy() const {
+  return nil;
+}
 
 }  // namespace web