diff --git a/gfx/layers/ipc/CompositorParent.cpp b/gfx/layers/ipc/CompositorParent.cpp
index 5877d1b76f52..b1b4b4c30bb5 100644
--- a/gfx/layers/ipc/CompositorParent.cpp
+++ b/gfx/layers/ipc/CompositorParent.cpp
@@ -1015,9 +1015,6 @@ EraseLayerState(uint64_t aId)
 CompositorParent::DeallocateLayerTreeId(uint64_t aId)
 {
   MOZ_ASSERT(NS_IsMainThread());
-  // Here main thread notifies compositor to remove an element from
-  // sIndirectLayerTrees. This removed element might be queried soon.
-  // Checking the elements of sIndirectLayerTrees exist or not before using.
   CompositorLoop()->PostTask(FROM_HERE,
                              NewRunnableFunction(&EraseLayerState, aId));
 }
@@ -1239,15 +1236,9 @@ CrossProcessCompositorParent::AllocPLayerTransactionParent(const nsTArray<Layers
 {
   MOZ_ASSERT(aId != 0);
 
-  CompositorParent::LayerTreeState* state = nullptr;
-  LayerTreeMap::iterator itr = sIndirectLayerTrees.find(aId);
-  if (sIndirectLayerTrees.end() != itr) {
-    state = &itr->second;
-  }
-
-  if (state && state->mLayerManager) {
-    state->mCrossProcessParent = this;
-    LayerManagerComposite* lm = state->mLayerManager;
+  if (sIndirectLayerTrees[aId].mLayerManager) {
+    sIndirectLayerTrees[aId].mCrossProcessParent = this;
+    LayerManagerComposite* lm = sIndirectLayerTrees[aId].mLayerManager;
     *aTextureFactoryIdentifier = lm->GetCompositor()->GetTextureFactoryIdentifier();
     *aSuccess = true;
     LayerTransactionParent* p = new LayerTransactionParent(lm, this, aId);
@@ -1276,13 +1267,7 @@ CrossProcessCompositorParent::DeallocPLayerTransactionParent(PLayerTransactionPa
 bool
 CrossProcessCompositorParent::RecvNotifyChildCreated(const uint64_t& child)
 {
-  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(child);
-  if (!state) {
-    return false;
-  }
-
-  MOZ_ASSERT(state->mParent);
-  state->mParent->NotifyChildCreated(child);
+  sIndirectLayerTrees[child].mParent->NotifyChildCreated(child);
   return true;
 }
 
@@ -1296,13 +1281,9 @@ CrossProcessCompositorParent::ShadowLayersUpdated(
   uint64_t id = aLayerTree->GetId();
 
   MOZ_ASSERT(id != 0);
+  MOZ_ASSERT(sIndirectLayerTrees[id].mParent);
 
-  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(id);
-  if (!state) {
-    return;
-  }
-  MOZ_ASSERT(state->mParent);
-  state->mParent->ScheduleRotationOnCompositorThread(aTargetConfig, aIsFirstPaint);
+  sIndirectLayerTrees[id].mParent->ScheduleRotationOnCompositorThread(aTargetConfig, aIsFirstPaint);
 
   Layer* shadowRoot = aLayerTree->GetRoot();
   if (shadowRoot) {
@@ -1310,7 +1291,7 @@ CrossProcessCompositorParent::ShadowLayersUpdated(
   }
   UpdateIndirectTree(id, shadowRoot, aTargetConfig);
 
-  state->mParent->NotifyShadowTreeTransaction(id, aIsFirstPaint, aScheduleComposite);
+  sIndirectLayerTrees[id].mParent->NotifyShadowTreeTransaction(id, aIsFirstPaint, aScheduleComposite);
 }
 
 void
@@ -1327,13 +1308,7 @@ CrossProcessCompositorParent::SetTestSampleTime(
 {
   uint64_t id = aLayerTree->GetId();
   MOZ_ASSERT(id != 0);
-  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(id);
-  if (!state) {
-    return false;
-  }
-
-  MOZ_ASSERT(state->mParent);
-  return state->mParent->SetTestSampleTime(aLayerTree, aTime);
+  return sIndirectLayerTrees[id].mParent->SetTestSampleTime(aLayerTree, aTime);
 }
 
 void
@@ -1341,26 +1316,14 @@ CrossProcessCompositorParent::LeaveTestMode(LayerTransactionParent* aLayerTree)
 {
   uint64_t id = aLayerTree->GetId();
   MOZ_ASSERT(id != 0);
-  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(id);
-  if (!state) {
-    return;
-  }
-
-  MOZ_ASSERT(state->mParent);
-  state->mParent->LeaveTestMode(aLayerTree);
+  sIndirectLayerTrees[id].mParent->LeaveTestMode(aLayerTree);
 }
 
 AsyncCompositionManager*
 CrossProcessCompositorParent::GetCompositionManager(LayerTransactionParent* aLayerTree)
 {
   uint64_t id = aLayerTree->GetId();
-  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(id);
-  if (!state) {
-    return nullptr;
-  }
-
-  MOZ_ASSERT(state->mParent);
-  return state->mParent->GetCompositionManager(aLayerTree);
+  return sIndirectLayerTrees[id].mParent->GetCompositionManager(aLayerTree);
 }
 
 void