Bug 1400440 - Re-enable apz.frame_delay.enabled on Fennec Nightly. r=kats

MozReview-Commit-ID: E7Ukb76vMep

--HG--
extra : rebase_source : 5cfeccb1e21959e5614d0da70f60bf9ad548154f

mobile/android/app/mobile.js

@@ -574,8 +574,11 @@ pref("apz.second_tap_tolerance", "0.3");
 pref("apz.touch_move_tolerance", "0.03");
 pref("apz.touch_start_tolerance", "0.06");
 
-// Enabling this on Fennec is blocked on a proper fix for bug 1390145.
+#ifdef NIGHTLY_BUILD
+pref("apz.frame_delay.enabled", true);
+#else
 pref("apz.frame_delay.enabled", false);
+#endif
 
 pref("layers.progressive-paint", true);
 pref("layers.low-precision-buffer", true);