add --enable-spatial-navigation flag for testing

webkit/glue/webpreferences.cc

Index: webkit/glue/webpreferences.cc
diff --git a/webkit/glue/webpreferences.cc b/webkit/glue/webpreferences.cc
index b07dd0d3945d8e3997b6fd43a4c6c5f7b857cf0e..4a96d38db3b09f4ddfe34ba2156573d49d54d29b 100644
--- a/webkit/glue/webpreferences.cc
+++ b/webkit/glue/webpreferences.cc
@@ -138,6 +138,7 @@ WebPreferences::WebPreferences()
 #else
       smart_insert_delete_enabled(false),
 #endif
+      spatial_navigation_enabled(false),
       cookie_enabled(true)
 #if defined(OS_ANDROID)
       ,
@@ -458,6 +459,9 @@ void WebPreferences::Apply(WebView* web_view) const {
   settings->setInitializeAtMinimumPageScale(initialize_at_minimum_page_scale);
 
   settings->setSmartInsertDeleteEnabled(smart_insert_delete_enabled);
+
+  settings->setSpatialNavigationEnabled(spatial_navigation_enabled);
+
   settings->setSelectionIncludesAltImageText(true);
 
 #if defined(OS_ANDROID)