Bug 1250924 - Disable displayport expiry on B2G because it causes the screen to go back while adjusting volume. r=gerard-majax

MozReview-Commit-ID: 3qXrgL2oQWS

--HG--
extra : rebase_source : 9e35b7feb55894b6b544b849e3c0dee2c77376fe

b2g/app/b2g.js

@@ -1025,6 +1025,7 @@ pref("apz.fling_curve_threshold_inches_per_ms", "0.01");
 pref("apz.fling_friction", "0.0019");
 pref("apz.max_velocity_inches_per_ms", "0.07");
 pref("apz.overscroll.enabled", true);
+pref("apz.displayport_expiry_ms", 0); // causes issues on B2G, see bug 1250924
 
 // For event-regions based hit-testing
 pref("layout.event-regions.enabled", true);