--- a/gfx/ipc/CompositorOptions.h
+++ b/gfx/ipc/CompositorOptions.h
@@ -40,16 +40,21 @@ public:
     : mUseAPZ(aUseAPZ)
     , mUseWebRender(aUseWebRender)
   {
   }
 
   bool UseAPZ() const { return mUseAPZ; }
   bool UseWebRender() const { return mUseWebRender; }
 
+  bool operator==(const CompositorOptions& aOther) {
+    return mUseAPZ == aOther.mUseAPZ &&
+           mUseWebRender == aOther.mUseWebRender;
+  }
+
   friend struct IPC::ParamTraits<CompositorOptions>;
 
 private:
   bool mUseAPZ;
   bool mUseWebRender;
 
   // Make sure to add new fields to the ParamTraits implementation
 };

--- a/gfx/layers/ipc/CompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/CompositorBridgeParent.cpp
@@ -1586,16 +1586,19 @@ CompositorBridgeParent::RecvMapAndNotify
 }
 
 mozilla::ipc::IPCResult
 CompositorBridgeParent::RecvAdoptChild(const uint64_t& child)
 {
   APZCTreeManagerParent* parent;
   {
     MonitorAutoLock lock(*sIndirectLayerTreesLock);
+    // We currently don't support adopting children from one compositor to
+    // another if the two compositors don't have the same options.
+    MOZ_ASSERT(sIndirectLayerTrees[child].mParent->mOptions == mOptions);
     NotifyChildCreated(child);
     if (sIndirectLayerTrees[child].mLayerTree) {
       sIndirectLayerTrees[child].mLayerTree->SetLayerManager(mLayerManager);
     }
     parent = sIndirectLayerTrees[child].mApzcTreeManagerParent;
   }
 
   if (mApzcTreeManager && parent) {

--- a/layout/ipc/RenderFrameParent.cpp
+++ b/layout/ipc/RenderFrameParent.cpp
@@ -211,17 +211,16 @@ RenderFrameParent::OwnerContentChanged(n
 {
   MOZ_ASSERT(!mFrameLoader || mFrameLoader->GetOwnerContent() == aContent,
              "Don't build new map if owner is same!");
 
   RefPtr<LayerManager> lm = mFrameLoader ? GetFrom(mFrameLoader) : nullptr;
   // Perhaps the document containing this frame currently has no presentation?
   if (lm && lm->GetCompositorBridgeChild()) {
     mLayersConnected = lm->GetCompositorBridgeChild()->SendAdoptChild(mLayersId);
-    lm->GetCompositorBridgeChild()->SendGetCompositorOptions(mLayersId, &mCompositorOptions);
     FrameLayerBuilder::InvalidateAllLayers(lm);
   }
 }
 
 void
 RenderFrameParent::ActorDestroy(ActorDestroyReason why)
 {
   if (mLayersId != 0) {