[Cleanup] Avoid using deprecated v8::Function::Call in supervised_user_error_page.

BUG=v8:7290,v8:8238

Change-Id: I4e44d97dfde85b471ed4e6b38f4e32374462de95
Reviewed-on: https://chromium-review.googlesource.com/c/1349342Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610595}

components/supervised_user_error_page/gin_wrapper.cc

@@ -100,7 +100,8 @@ void GinWrapper::OnAccessRequestAdded(bool success) {
   v8::MicrotasksScope microtasks(isolate,
                                  v8::MicrotasksScope::kDoNotRunMicrotasks);
 
-  callback->Call(context->Global(), 1, &args);
+  callback->Call(context, context->Global(), 1, &args)
+      .FromMaybe(v8::Local<v8::Value>());
 }
 
 gin::ObjectTemplateBuilder GinWrapper::GetObjectTemplateBuilder(