[epiphany/pgriffis/web-extension/background-page] WebExtensions: runtime.getBackgroundPage() should return a Promise

[Marge Bot <marge-bot src gnome org>]

commit f2e55e9192eb0d9047fcda53440eda953743e649
Author: Patrick Griffis <pgriffis igalia com>
Date:   Wed Jun 8 17:08:59 2022 -0500

    WebExtensions: runtime.getBackgroundPage() should return a Promise
    
    Part-of: <https://gitlab.gnome.org/GNOME/epiphany/-/merge_requests/1140>

 embed/web-process-extension/resources/js/webextensions.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/embed/web-process-extension/resources/js/webextensions.js 
b/embed/web-process-extension/resources/js/webextensions.js
index db4d9d08c..520729203 100644
--- a/embed/web-process-extension/resources/js/webextensions.js
+++ b/embed/web-process-extension/resources/js/webextensions.js
@@ -65,8 +65,8 @@ window.browser.extension.getViews = function (fetchProperties) {
 window.browser.extension.getBackgroundPage = function () {
     const views = window.browser.extension.getViews({type: 'background'});
     if (!views)
-        return null;
-    return views[0];
+        return Promise.resolve(null);
+    return Promise.resolve(views[0]);
 };
 
 // browser.runtime is defined in webextensions-common.js