Back out cset 156e0990abc8 (bug 1246676) since it's not needed any more. r=backout

modules/libpref/init/all.js

@@ -568,16 +568,7 @@ pref("apz.content_response_timeout", 300);
 pref("apz.drag.enabled", false);
 pref("apz.danger_zone_x", 50);
 pref("apz.danger_zone_y", 100);
-
-// See bug 1246676, we're experimenting to see what's best
-#if defined(XP_WIN)
-pref("apz.displayport_expiry_ms", 0);
-#elif defined(XP_MACOSX)
-pref("apz.displayport_expiry_ms", 30000);
-#else
 pref("apz.displayport_expiry_ms", 15000);
-#endif
-
 pref("apz.enlarge_displayport_when_clipped", false);
 pref("apz.fling_accel_base_mult", "1.0");
 pref("apz.fling_accel_interval_ms", 500);