From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Samuel Attard <sattard@slack-corp.com>
Date: Mon, 8 Mar 2021 16:27:39 -0800
Subject: extend ApplyWebPreferences with Electron-specific logic

On macOS, popup menus are rendered by the main process by default.
This causes problems in OSR, since when the popup is rendered separately,
it won't be captured in the rendered image.
Offscreen can be updated at runtime, as such we need to apply the
turn on/off ExternalPopupMenu in the ApplyPreferences method.
There is no current way to attach an observer to these prefs so patching
is our only option.

Ideally we could add an embedder observer pattern here but that can be
done in future work.

diff --git a/third_party/blink/renderer/core/exported/web_view_impl.cc b/third_party/blink/renderer/core/exported/web_view_impl.cc
index b9799837c7ce14fc76045700b30e1358d4705251..5b3ab0837b5a85b4e7dd1685db75f65cd4d5ff43 100644
--- a/third_party/blink/renderer/core/exported/web_view_impl.cc
+++ b/third_party/blink/renderer/core/exported/web_view_impl.cc
@@ -1890,6 +1890,8 @@ void WebView::ApplyWebPreferences(const web_pref::WebPreferences& prefs,
 #if BUILDFLAG(IS_MAC)
   web_view_impl->SetMaximumLegibleScale(
       prefs.default_maximum_page_scale_factor);
+  web_view_impl->GetChromeClient().SetUseExternalPopupMenusForTesting(
+      !prefs.offscreen);
 #endif
 
 #if BUILDFLAG(IS_WIN)