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 b627f400d16ee1c605ef7657dc3ba63319c5fd56..455b0fd461d0c32de39800d4d7cef2ceb30dc7fb 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"
@@ -1792,6 +1793,16 @@ 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() {