Backed out changeset dd917f920d7f (bug 1694248) for causing wpt failures. CLOSED TREE

modules/libpref/init/all.js

@@ -4398,7 +4398,11 @@ pref("toolkit.aboutProcesses.showThreads", false);
   pref("toolkit.crashreporter.include_context_heap", true);
 #endif
 
-pref("layers.omtp.enabled", false);
+#if defined(XP_WIN) || defined(XP_MACOSX) || defined(MOZ_WIDGET_GTK)
+  pref("layers.omtp.enabled", true);
+#else
+  pref("layers.omtp.enabled", false);
+#endif
 
 // Support for legacy customizations that rely on checking the
 // user profile directory for these stylesheets: