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 f2a332453e3bd421ff563a0b11c1aae5ef185db2..655fc4ee7a3f38bec066c49ff628616d3e09370d 100644
--- a/third_party/blink/renderer/core/exported/web_view_impl.cc
+++ b/third_party/blink/renderer/core/exported/web_view_impl.cc
@@ -1884,6 +1884,8 @@ 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)