[epiphany/wip/exalm/gesture] Enable back/forward gesture in WebKit

[Alexander Mikhaylenko <alexm src gnome org>]

commit 6fd854d0cb39bb17526bef3b8c81702dd1eec020
Author: Alexander Mikhaylenko <exalm7659 gmail com>
Date:   Sun Jan 27 19:30:22 2019 +0500

    Enable back/forward gesture in WebKit
    
    WebKit 2.23.4 has a built-in gesture for back/forward navigation, so enable
    it.

 embed/ephy-embed-prefs.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/embed/ephy-embed-prefs.c b/embed/ephy-embed-prefs.c
index a3cd389d5..10600fde4 100644
--- a/embed/ephy-embed-prefs.c
+++ b/embed/ephy-embed-prefs.c
@@ -492,6 +492,9 @@ ephy_embed_prefs_init (gpointer user_data)
                                                        "enable-dns-prefetching", TRUE,
                                                        "enable-mediasource", TRUE,
                                                        "javascript-can-open-windows-automatically", TRUE,
+#if WEBKIT_CHECK_VERSION(2, 23, 4)
+                                                       "enable-back-forward-navigation-gestures", TRUE,
+#endif
                                                        NULL);
 
   for (i = 0; i < G_N_ELEMENTS (webkit_pref_entries); i++) {