--- a/dom/base/TimeoutManager.cpp
+++ b/dom/base/TimeoutManager.cpp
@@ -707,18 +707,18 @@ TimeoutManager::CancelOrUpdateBackPressu
 
   // If the delay has decreased, though, we only apply the new value if it has
   // reduced significantly.  This hysteresis avoids thrashing the back pressure
   // value back and forth rapidly.  This is important because reducing the
   // backpressure delay requires calling ResetTimerForThrottleReduction() which
   // can be quite expensive.  We only want to call that method if the back log
   // is really clearing.
   else if (newBackPressureDelayMS == 0 ||
-           (newBackPressureDelayMS <=
-           (mBackPressureDelayMS - kBackPressureDelayReductionThresholdMS))) {
+           (mBackPressureDelayMS >
+           (newBackPressureDelayMS + kBackPressureDelayReductionThresholdMS))) {
     int32_t oldBackPressureDelayMS = mBackPressureDelayMS;
     mBackPressureDelayMS = newBackPressureDelayMS;
 
     // If the back pressure delay has gone down we must reset any existing
     // timers to use the new value.  Otherwise we run the risk of executing
     // timer callbacks out-of-order.
     ResetTimersForThrottleReduction(oldBackPressureDelayMS);
   }