diff --git a/gfx/layers/apz/public/APZSampler.h b/gfx/layers/apz/public/APZSampler.h
index b520982c0873..15aff4f9d4aa 100644
--- a/gfx/layers/apz/public/APZSampler.h
+++ b/gfx/layers/apz/public/APZSampler.h
@@ -92,13 +92,6 @@ public:
   void MarkAsyncTransformAppliedToContent(const LayerMetricsWrapper& aLayer);
   bool HasUnusedAsyncTransform(const LayerMetricsWrapper& aLayer);
 
-  /**
-   * Return a new AutoApplyAsyncTestAttributes instance. This should be called
-   * whenever we need to apply async attributes for test purposes (namely
-   * reftest-async-scroll-{x,y} and reftest-async-zoom).
-   */
-  UniquePtr<AutoApplyAsyncTestAttributes> ApplyAsyncTestAttributes(const LayerMetricsWrapper& aLayer);
-
   /**
    * This can be used to assert that the current thread is the
    * sampler thread (which samples the async transform).
diff --git a/gfx/layers/apz/src/APZCTreeManager.cpp b/gfx/layers/apz/src/APZCTreeManager.cpp
index 719642f3c67a..723b2fd38622 100644
--- a/gfx/layers/apz/src/APZCTreeManager.cpp
+++ b/gfx/layers/apz/src/APZCTreeManager.cpp
@@ -604,7 +604,7 @@ APZCTreeManager::SampleForWebRender(wr::TransactionWrapper& aTxn,
 
     // Apply any additional async scrolling for testing purposes (used for
     // reftest-async-scroll and reftest-async-zoom).
-    auto _ = MakeUnique<AutoApplyAsyncTestAttributes>(apzc);
+    AutoApplyAsyncTestAttributes testAttributeApplier(apzc);
 
     ParentLayerPoint layerTranslation = apzc->GetCurrentAsyncTransform(
         AsyncPanZoomController::eForCompositing).mTranslation;
@@ -3061,7 +3061,7 @@ APZCTreeManager::ComputeTransformForNode(const HitTestingTreeNode* aNode) const
   if (AsyncPanZoomController* apzc = aNode->GetApzc()) {
     // Apply any additional async scrolling for testing purposes (used for
     // reftest-async-scroll and reftest-async-zoom).
-    auto _ = MakeUnique<AutoApplyAsyncTestAttributes>(apzc);
+    AutoApplyAsyncTestAttributes testAttributeApplier(apzc);
     // If the node represents scrollable content, apply the async transform
     // from its APZC.
     return aNode->GetTransform() *
@@ -3153,7 +3153,7 @@ APZCTreeManager::ComputeTransformForScrollThumb(
 
   // Apply any additional async scrolling for testing purposes (used for
   // reftest-async-scroll and reftest-async-zoom).
-  auto _ = MakeUnique<AutoApplyAsyncTestAttributes>(aApzc);
+  AutoApplyAsyncTestAttributes testAttributeApplier(aApzc);
 
   AsyncTransformComponentMatrix asyncTransform =
     aApzc->GetCurrentAsyncTransform(AsyncPanZoomController::eForCompositing);
diff --git a/gfx/layers/apz/src/APZSampler.cpp b/gfx/layers/apz/src/APZSampler.cpp
index 3e41e5b20513..0350ad6ad2c5 100644
--- a/gfx/layers/apz/src/APZSampler.cpp
+++ b/gfx/layers/apz/src/APZSampler.cpp
@@ -233,16 +233,6 @@ APZSampler::HasUnusedAsyncTransform(const LayerMetricsWrapper& aLayer)
       && !AsyncTransformComponentMatrix(apzc->GetCurrentAsyncTransform(AsyncPanZoomController::eForCompositing)).IsIdentity();
 }
 
-UniquePtr<AutoApplyAsyncTestAttributes>
-APZSampler::ApplyAsyncTestAttributes(const LayerMetricsWrapper& aLayer)
-{
-  MOZ_ASSERT(CompositorThreadHolder::IsInCompositorThread());
-  AssertOnSamplerThread();
-
-  MOZ_ASSERT(aLayer.GetApzc());
-  return MakeUnique<AutoApplyAsyncTestAttributes>(aLayer.GetApzc());
-}
-
 void
 APZSampler::AssertOnSamplerThread() const
 {
diff --git a/gfx/layers/apz/src/APZUtils.h b/gfx/layers/apz/src/APZUtils.h
index 38468af71947..593e2ca186fa 100644
--- a/gfx/layers/apz/src/APZUtils.h
+++ b/gfx/layers/apz/src/APZUtils.h
@@ -104,7 +104,7 @@ struct TargetConfirmationFlags {
  * An RAII class to temporarily apply async test attributes to the provided
  * AsyncPanZoomController.
  */
-class AutoApplyAsyncTestAttributes {
+class MOZ_RAII AutoApplyAsyncTestAttributes {
 public:
   explicit AutoApplyAsyncTestAttributes(AsyncPanZoomController*);
   ~AutoApplyAsyncTestAttributes();
diff --git a/gfx/layers/composite/AsyncCompositionManager.cpp b/gfx/layers/composite/AsyncCompositionManager.cpp
index 7e1eff23073c..3273ca99487f 100644
--- a/gfx/layers/composite/AsyncCompositionManager.cpp
+++ b/gfx/layers/composite/AsyncCompositionManager.cpp
@@ -979,7 +979,7 @@ AsyncCompositionManager::ApplyAsyncContentTransformToTree(Layer *aLayer,
 
             // Apply any additional async scrolling for testing purposes (used
             // for reftest-async-scroll and reftest-async-zoom).
-            auto _ = sampler->ApplyAsyncTestAttributes(wrapper);
+            AutoApplyAsyncTestAttributes testAttributeApplier(wrapper.GetApzc());
 
             const FrameMetrics& metrics = wrapper.Metrics();
             MOZ_ASSERT(metrics.IsScrollable());