Bug 1406825 - Enable Custom Elements on Nightly by default; r=smaug

MozReview-Commit-ID: 7MsdZPy2sjZ

--HG--
extra : rebase_source : e5d715411aee8a186494a6c7af6998f05b4f0fb7

modules/libpref/init/all.js

@@ -1394,7 +1394,11 @@ pref("dom.event.highrestimestamp.enabled",  true);
 pref("dom.event.coalesce_mouse_move",       true);
 
 pref("dom.webcomponents.enabled",           false);
+#ifdef NIGHTLY_BUILD
+pref("dom.webcomponents.customelements.enabled", true);
+#else
 pref("dom.webcomponents.customelements.enabled", false);
+#endif
 
 pref("javascript.enabled",                  true);
 pref("javascript.options.strict",           false);