Bug 782327 - Enable OMTC async video on Android. r=blassey

Set layers.async-video.enabled to true and remove the css rule that forced
nearest-neighbour scaling on video.

mobile/android/app/mobile.js

@@ -539,6 +539,7 @@ pref("ui.dragThresholdY", 25);
 
 pref("layers.acceleration.disabled", false);
 pref("layers.offmainthreadcomposition.enabled", true);
+pref("layers.async-video.enabled", true);
 
 pref("notification.feature.enabled", true);
 

mobile/android/themes/core/content.css

@@ -316,14 +316,6 @@ input > .anonymous-div:after {
   margin: 16px;
 }
 
-/*
- * Enforce nearest scaling for video in order not to lose too much performance
- * after fixing bug 598736 ("Use higher-quality imageinterpolation on mobile")
- */
-video {
-    image-rendering: -moz-crisp-edges;
-}
-
 xul|menulist {
   -moz-binding: url("chrome://browser/content/bindings/menulist.xml#menulist");
 }