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

background_color can be updated at runtime, as such we need to apply the
new background color to the WebView 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 90636a53231ce906a57e30596ebe8385802cecfa..259f945f0117ced38a24aa0dda0a845f9f8bf955 100644
--- a/third_party/blink/renderer/core/exported/web_view_impl.cc
+++ b/third_party/blink/renderer/core/exported/web_view_impl.cc
@@ -155,6 +155,7 @@
 #include "third_party/blink/renderer/core/timing/dom_window_performance.h"
 #include "third_party/blink/renderer/core/timing/window_performance.h"
 #include "third_party/blink/renderer/platform/fonts/font_cache.h"
+#include "third_party/blink/renderer/platform/graphics/color.h"
 #include "third_party/blink/renderer/platform/graphics/image.h"
 #include "third_party/blink/renderer/platform/graphics/paint/cull_rect.h"
 #include "third_party/blink/renderer/platform/graphics/paint/paint_record_builder.h"
@@ -1747,6 +1748,16 @@ void WebView::ApplyWebPreferences(const web_pref::WebPreferences& prefs,
 
   RuntimeEnabledFeatures::SetTranslateServiceEnabled(
       prefs.translate_service_available);
+
+  SkColor color = SK_ColorTRANSPARENT;
+  if (!prefs.guest_instance_id) {  // not inside electron <webview /> tag, which is always transparent.
+    Color blink_color;
+    if (blink_color.SetFromString(WebString::FromASCII(prefs.background_color)))
+      color = static_cast<SkColor>(blink_color);
+  }
+  web_view->SetBaseBackgroundColor(color);
+
+  SetUseExternalPopupMenus(!prefs.offscreen);
 }
 
 void WebViewImpl::ThemeChanged() {