tdf#129327: Ignore all keydown events at the outermost level for iOS

Possibly a good idea for Android, too? See bug report for description
of what this fixes.

Change-Id: I6b70f431ced09044756c2edc3fcc2542428b62e1
Reviewed-on: https://gerrit.libreoffice.org/c/online/+/86484
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Tor Lillqvist <tml@collabora.com>
diff --git a/loleaflet/html/loleaflet.html.m4 b/loleaflet/html/loleaflet.html.m4
index 7639bf9..ad6d90f 100644
--- a/loleaflet/html/loleaflet.html.m4
+++ b/loleaflet/html/loleaflet.html.m4
@@ -65,6 +65,10 @@
  [   window.ThisIsTheAndroidApp = false;]
)

if (window.ThisIsTheiOSApp) {
  window.addEventListener("keydown", function(e) { e.preventDefault(); });
}

var Base64ToArrayBuffer = function(base64Str) {
  var binStr = atob(base64Str);
  var ab = new ArrayBuffer(binStr.length);