--- a/gfx/layers/ipc/CompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/CompositorBridgeParent.cpp
@@ -445,16 +445,28 @@ CompositorBridgeParent::StopAndClearReso
 {
   if (mForceCompositionTask) {
     mForceCompositionTask->Cancel();
     mForceCompositionTask = nullptr;
   }
 
   mPaused = true;
 
+  // We need to clear the APZ tree before we destroy the WebRender API below,
+  // because in the case of async scene building that will shut down the updater
+  // thread and we need to run the task before that happens.
+  MOZ_ASSERT((mApzSampler != nullptr) == (mApzcTreeManager != nullptr));
+  MOZ_ASSERT((mApzUpdater != nullptr) == (mApzcTreeManager != nullptr));
+  if (mApzUpdater) {
+    mApzSampler = nullptr;
+    mApzUpdater->ClearTree(mRootLayerTreeID);
+    mApzUpdater = nullptr;
+    mApzcTreeManager = nullptr;
+  }
+
   // Ensure that the layer manager is destroyed before CompositorBridgeChild.
   if (mLayerManager) {
     MonitorAutoLock lock(*sIndirectLayerTreesLock);
     ForEachIndirectLayerTree([this] (LayerTreeState* lts, LayersId) -> void {
       mLayerManager->ClearCachedResources(lts->mRoot);
       lts->mLayerManager = nullptr;
       lts->mParent = nullptr;
     });
@@ -634,25 +646,16 @@ CompositorBridgeParent::ActorDestroy(Act
   mCanSend = false;
 
   StopAndClearResources();
 
   RemoveCompositor(mCompositorBridgeID);
 
   mCompositionManager = nullptr;
 
-  MOZ_ASSERT((mApzSampler != nullptr) == (mApzcTreeManager != nullptr));
-  MOZ_ASSERT((mApzUpdater != nullptr) == (mApzcTreeManager != nullptr));
-  if (mApzUpdater) {
-    mApzSampler = nullptr;
-    mApzUpdater->ClearTree(mRootLayerTreeID);
-    mApzUpdater = nullptr;
-    mApzcTreeManager = nullptr;
-  }
-
   { // scope lock
     MonitorAutoLock lock(*sIndirectLayerTreesLock);
     sIndirectLayerTrees.erase(mRootLayerTreeID);
   }
 
   // There are chances that the ref count reaches zero on the main thread shortly
   // after this function returns while some ipdl code still needs to run on
   // this thread.