PlzNavigate: support the WebRequest API

content/browser/frame_host/navigator_delegate.cc

Index: content/browser/frame_host/navigator_delegate.cc
diff --git a/content/browser/frame_host/navigator_delegate.cc b/content/browser/frame_host/navigator_delegate.cc
index 95deec6d903c13c54026ec47ba220d4ddf98adbc..1d4e3e766a72c9b44d74a81f573471adbf41f3a9 100644
--- a/content/browser/frame_host/navigator_delegate.cc
+++ b/content/browser/frame_host/navigator_delegate.cc
@@ -25,4 +25,9 @@ NavigatorDelegate::CreateThrottlesForNavigation(
   return ScopedVector<NavigationThrottle>();
 }
 
+std::unique_ptr<NavigationUIData> NavigatorDelegate::GetNavigationUIData(
+    NavigationHandle* navigation_handle) {
+  return nullptr;
+}
+
 }  // namespace content