--- a/gfx/layers/ipc/CompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/CompositorBridgeParent.cpp
@@ -1303,20 +1303,20 @@ CompositorBridgeParent::GetAnimationStor
 mozilla::ipc::IPCResult
 CompositorBridgeParent::RecvGetFrameUniformity(FrameUniformityData* aOutData)
 {
   mCompositionManager->GetFrameUniformity(aOutData);
   return IPC_OK();
 }
 
 void
-CompositorBridgeParent::FlushApzRepaints(const LayerTransactionParent* aLayerTree)
+CompositorBridgeParent::FlushApzRepaints(const uint64_t& aLayersId)
 {
   MOZ_ASSERT(mApzcTreeManager);
-  uint64_t layersId = aLayerTree->GetId();
+  uint64_t layersId = aLayersId;
   if (layersId == 0) {
     // The request is coming from the parent-process layer tree, so we should
     // use the compositor's root layer tree id.
     layersId = mRootLayerTreeID;
   }
   RefPtr<CompositorBridgeParent> self = this;
   APZThreadUtils::RunOnControllerThread(NS_NewRunnableFunction([=] () {
     self->mApzcTreeManager->FlushApzRepaints(layersId);

--- a/gfx/layers/ipc/CompositorBridgeParent.h
+++ b/gfx/layers/ipc/CompositorBridgeParent.h
@@ -103,17 +103,17 @@ public:
   virtual void NotifyClearCachedResources(LayerTransactionParent* aLayerTree) { }
 
   virtual void ForceComposite(LayerTransactionParent* aLayerTree) { }
   virtual bool SetTestSampleTime(LayerTransactionParent* aLayerTree,
                                  const TimeStamp& aTime) { return true; }
   virtual void LeaveTestMode(LayerTransactionParent* aLayerTree) { }
   virtual void ApplyAsyncProperties(LayerTransactionParent* aLayerTree) = 0;
   virtual CompositorAnimationStorage* GetAnimationStorage(const uint64_t& aId) { return nullptr; }
-  virtual void FlushApzRepaints(const LayerTransactionParent* aLayerTree) = 0;
+  virtual void FlushApzRepaints(const uint64_t& aLayersId) = 0;
   virtual void GetAPZTestData(const LayerTransactionParent* aLayerTree,
                               APZTestData* aOutData) { }
   virtual void SetConfirmedTargetAPZC(const LayerTransactionParent* aLayerTree,
                                       const uint64_t& aInputBlockId,
                                       const nsTArray<ScrollableLayerGuid>& aTargets) = 0;
   virtual void UpdatePaintTime(LayerTransactionParent* aLayerTree, const TimeDuration& aPaintTime) {}
 
   virtual ShmemAllocator* AsShmemAllocator() override { return this; }
@@ -226,17 +226,17 @@ public:
                                    bool aHitTestUpdate) override;
   virtual void ForceComposite(LayerTransactionParent* aLayerTree) override;
   virtual bool SetTestSampleTime(LayerTransactionParent* aLayerTree,
                                  const TimeStamp& aTime) override;
   virtual void LeaveTestMode(LayerTransactionParent* aLayerTree) override;
   virtual void ApplyAsyncProperties(LayerTransactionParent* aLayerTree)
                override;
   virtual CompositorAnimationStorage* GetAnimationStorage(const uint64_t& aId) override;
-  virtual void FlushApzRepaints(const LayerTransactionParent* aLayerTree) override;
+  virtual void FlushApzRepaints(const uint64_t& aLayersId) override;
   virtual void GetAPZTestData(const LayerTransactionParent* aLayerTree,
                               APZTestData* aOutData) override;
   virtual void SetConfirmedTargetAPZC(const LayerTransactionParent* aLayerTree,
                                       const uint64_t& aInputBlockId,
                                       const nsTArray<ScrollableLayerGuid>& aTargets) override;
   virtual AsyncCompositionManager* GetCompositionManager(LayerTransactionParent* aLayerTree) override { return mCompositionManager; }
 
   virtual PTextureParent* AllocPTextureParent(const SurfaceDescriptor& aSharedData,

--- a/gfx/layers/ipc/CrossProcessCompositorBridgeParent.cpp
+++ b/gfx/layers/ipc/CrossProcessCompositorBridgeParent.cpp
@@ -417,28 +417,27 @@ CrossProcessCompositorBridgeParent::GetA
   }
 
   MOZ_ASSERT(state->mParent);
   // GetAnimationStorage in CompositorBridgeParent expects id as 0
   return state->mParent->GetAnimationStorage(0);
 }
 
 void
-CrossProcessCompositorBridgeParent::FlushApzRepaints(const LayerTransactionParent* aLayerTree)
+CrossProcessCompositorBridgeParent::FlushApzRepaints(const uint64_t& aLayersId)
 {
-  uint64_t id = aLayerTree->GetId();
-  MOZ_ASSERT(id != 0);
+  MOZ_ASSERT(aLayersId != 0);
   const CompositorBridgeParent::LayerTreeState* state =
-    CompositorBridgeParent::GetIndirectShadowTree(id);
+    CompositorBridgeParent::GetIndirectShadowTree(aLayersId);
   if (!state) {
     return;
   }
 
   MOZ_ASSERT(state->mParent);
-  state->mParent->FlushApzRepaints(aLayerTree);
+  state->mParent->FlushApzRepaints(aLayersId);
 }
 
 void
 CrossProcessCompositorBridgeParent::GetAPZTestData(
   const LayerTransactionParent* aLayerTree,
   APZTestData* aOutData)
 {
   uint64_t id = aLayerTree->GetId();

--- a/gfx/layers/ipc/CrossProcessCompositorBridgeParent.h
+++ b/gfx/layers/ipc/CrossProcessCompositorBridgeParent.h
@@ -99,17 +99,17 @@ public:
   virtual void NotifyClearCachedResources(LayerTransactionParent* aLayerTree) override;
   virtual bool SetTestSampleTime(LayerTransactionParent* aLayerTree,
                                  const TimeStamp& aTime) override;
   virtual void LeaveTestMode(LayerTransactionParent* aLayerTree) override;
   virtual void ApplyAsyncProperties(LayerTransactionParent* aLayerTree)
                override;
   virtual CompositorAnimationStorage*
     GetAnimationStorage(const uint64_t& aId) override;
-  virtual void FlushApzRepaints(const LayerTransactionParent* aLayerTree) override;
+  virtual void FlushApzRepaints(const uint64_t& aLayersId) override;
   virtual void GetAPZTestData(const LayerTransactionParent* aLayerTree,
                               APZTestData* aOutData) override;
   virtual void SetConfirmedTargetAPZC(const LayerTransactionParent* aLayerTree,
                                       const uint64_t& aInputBlockId,
                                       const nsTArray<ScrollableLayerGuid>& aTargets) override;
 
   virtual AsyncCompositionManager* GetCompositionManager(LayerTransactionParent* aParent) override;
   virtual mozilla::ipc::IPCResult RecvRemotePluginsReady()  override { return IPC_FAIL_NO_REASON(this); }

--- a/gfx/layers/ipc/LayerTransactionParent.cpp
+++ b/gfx/layers/ipc/LayerTransactionParent.cpp
@@ -839,17 +839,17 @@ LayerTransactionParent::RecvSetAsyncZoom
   }
   controller->SetTestAsyncZoom(LayerToParentLayerScale(aValue));
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult
 LayerTransactionParent::RecvFlushApzRepaints()
 {
-  mCompositorBridge->FlushApzRepaints(this);
+  mCompositorBridge->FlushApzRepaints(GetId());
   return IPC_OK();
 }
 
 mozilla::ipc::IPCResult
 LayerTransactionParent::RecvGetAPZTestData(APZTestData* aOutData)
 {
   mCompositorBridge->GetAPZTestData(this, aOutData);
   return IPC_OK();