diff --git a/gfx/layers/apz/src/APZCTreeManager.cpp b/gfx/layers/apz/src/APZCTreeManager.cpp
index 8f8fd8a43120..62d07a8951c3 100644
--- a/gfx/layers/apz/src/APZCTreeManager.cpp
+++ b/gfx/layers/apz/src/APZCTreeManager.cpp
@@ -3198,8 +3198,7 @@ already_AddRefed<wr::WebRenderAPI> APZCTreeManager::GetWebRenderAPIAtPoint(
   CompositorBridgeParent::CallWithIndirectShadowTree(
       mRootLayersId, [&](LayerTreeState& aState) -> void {
         if (aState.mWrBridge) {
-          IntPoint point = RoundedToInt(aPoint).ToUnknownPoint();
-          api = aState.mWrBridge->GetWebRenderAPIAtPoint(point);
+          api = aState.mWrBridge->GetWebRenderAPIAtPoint(aPoint);
         }
       });
   return api.forget();
diff --git a/gfx/layers/wr/WebRenderBridgeParent.cpp b/gfx/layers/wr/WebRenderBridgeParent.cpp
index a025ce1a01ce..e77c108e8eb5 100644
--- a/gfx/layers/wr/WebRenderBridgeParent.cpp
+++ b/gfx/layers/wr/WebRenderBridgeParent.cpp
@@ -914,7 +914,8 @@ bool WebRenderBridgeParent::SetDisplayList(
     if (IsRootWebRenderBridgeParent()) {
       if (aRenderRoot != wr::RenderRoot::Default) {
         MutexAutoLock lock(mRenderRootRectMutex);
-        mRenderRootRects[aRenderRoot] = RoundedToInt(aRect).ToUnknownRect();
+        mRenderRootRects[aRenderRoot] = ViewAs<ScreenPixel>(
+            aRect, PixelCastJustification::LayoutDeviceIsScreenForTabDims);
       }
       LayoutDeviceIntSize widgetSize = mWidget->GetClientSize();
       LayoutDeviceIntRect rect = RoundedToInt(aRect);
@@ -2019,7 +2020,7 @@ void WebRenderBridgeParent::HoldPendingTransactionId(
 }
 
 already_AddRefed<wr::WebRenderAPI>
-WebRenderBridgeParent::GetWebRenderAPIAtPoint(const gfx::IntPoint& aPoint) {
+WebRenderBridgeParent::GetWebRenderAPIAtPoint(const ScreenPoint& aPoint) {
   MutexAutoLock lock(mRenderRootRectMutex);
   for (auto renderRoot : wr::kNonDefaultRenderRoots) {
     if (mRenderRootRects[renderRoot].Contains(aPoint)) {
diff --git a/gfx/layers/wr/WebRenderBridgeParent.h b/gfx/layers/wr/WebRenderBridgeParent.h
index afc6dcf105a9..bdbbe269936f 100644
--- a/gfx/layers/wr/WebRenderBridgeParent.h
+++ b/gfx/layers/wr/WebRenderBridgeParent.h
@@ -80,7 +80,7 @@ class WebRenderBridgeParent final
     return true;
   }
   already_AddRefed<wr::WebRenderAPI> GetWebRenderAPIAtPoint(
-      const gfx::IntPoint& aPoint);
+      const ScreenPoint& aPoint);
   already_AddRefed<wr::WebRenderAPI> GetWebRenderAPI(
       wr::RenderRoot aRenderRoot) {
     if ((size_t)aRenderRoot >= mApis.Length()) {
@@ -468,7 +468,7 @@ class WebRenderBridgeParent final
   // Kind of clunky, but I can't sort out a more elegant way of getting this to
   // work.
   Mutex mRenderRootRectMutex;
-  wr::NonDefaultRenderRootArray<IntRect> mRenderRootRects;
+  wr::NonDefaultRenderRootArray<ScreenRect> mRenderRootRects;
 
   wr::RenderRoot mRenderRoot;
   bool mPaused;