--- a/gfx/layers/apz/src/APZCTreeManager.cpp
+++ b/gfx/layers/apz/src/APZCTreeManager.cpp
@@ -972,17 +972,17 @@ WillHandleInput(const PanGestureOrScroll
 }
 
 void
 APZCTreeManager::FlushApzRepaints(uint64_t aLayersId)
 {
   // Previously, paints were throttled and therefore this method was used to
   // ensure any pending paints were flushed. Now, paints are flushed
   // immediately, so it is safe to simply send a notification now.
-  APZCTM_LOG("Flushing repaints for layers id 0x%" PRIx64, aLayersId);
+  APZCTM_LOG("Flushing repaints for layers id 0x%" PRIx64 "\n", aLayersId);
   const LayerTreeState* state =
     CompositorBridgeParent::GetIndirectShadowTree(aLayersId);
   MOZ_ASSERT(state && state->mController);
   state->mController->DispatchToRepaintThread(
     NewRunnableMethod("layers::GeckoContentController::NotifyFlushComplete",
                       state->mController,
                       &GeckoContentController::NotifyFlushComplete));
 }