Backed out changeset 24fe1880f83b (bug 1126090) for b2g test failures

dom/events/EventStateManager.cpp

@@ -3011,13 +3011,7 @@ EventStateManager::PostHandleEvent(nsPresContext* aPresContext,
       }
 
       WidgetWheelEvent* wheelEvent = aEvent->AsWheelEvent();
-      WheelPrefs::Action action = WheelPrefs::GetInstance()->ComputeActionFor(wheelEvent);
+      switch (WheelPrefs::GetInstance()->ComputeActionFor(wheelEvent)) {
-      if (action == WheelPrefs::ACTION_SCROLL && gfxPrefs::AsyncPanZoomEnabled()) {
-        // When APZ is enabled, the actual scroll animation is handled by the
-        // compositor. Ignore it here.
-        action = WheelPrefs::ACTION_NONE;
-      }
-      switch (action) {
         case WheelPrefs::ACTION_SCROLL: {
           // For scrolling of default action, we should honor the mouse wheel
           // transaction.