diff --git a/layout/base/nsCSSFrameConstructor.cpp b/layout/base/nsCSSFrameConstructor.cpp
index f167c8c9905d..d883b6f06ec0 100644
--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -9868,14 +9868,12 @@ nsCSSFrameConstructor::CreateNeededAnonFlexOrGridItems(
     return;
   }
 
-  nsIAtom* containerType = aParentFrame->GetType();
   const bool isWebkitBox = nsFlexContainerFrame::IsLegacyBox(aParentFrame);
 
   FCItemIterator iter(aItems);
   do {
     // Advance iter past children that don't want to be wrapped
-    if (iter.SkipItemsThatDontNeedAnonFlexOrGridItem(aState, containerType,
-                                                     isWebkitBox)) {
+    if (iter.SkipItemsThatDontNeedAnonFlexOrGridItem(aState, isWebkitBox)) {
       // Hit the end of the items without finding any remaining children that
       // need to be wrapped. We're finished!
       return;
@@ -9898,9 +9896,7 @@ nsCSSFrameConstructor::CreateNeededAnonFlexOrGridItems(
       bool hitEnd = afterWhitespaceIter.SkipWhitespace(aState);
       bool nextChildNeedsAnonItem =
         !hitEnd &&
-        afterWhitespaceIter.item().NeedsAnonFlexOrGridItem(aState,
-                                                           containerType,
-                                                           isWebkitBox);
+        afterWhitespaceIter.item().NeedsAnonFlexOrGridItem(aState, isWebkitBox);
 
       if (!nextChildNeedsAnonItem) {
         // There's nothing after the whitespace that we need to wrap, so we
@@ -9914,8 +9910,7 @@ nsCSSFrameConstructor::CreateNeededAnonFlexOrGridItems(
         // we jump back to the beginning of the loop to skip over that child
         // (and anything else non-wrappable after it)
         MOZ_ASSERT(!iter.IsDone() &&
-                   !iter.item().NeedsAnonFlexOrGridItem(aState, containerType,
-                                                        isWebkitBox),
+                   !iter.item().NeedsAnonFlexOrGridItem(aState, isWebkitBox),
                    "hitEnd and/or nextChildNeedsAnonItem lied");
         continue;
       }
@@ -9925,15 +9920,14 @@ nsCSSFrameConstructor::CreateNeededAnonFlexOrGridItems(
     // anonymous flex/grid item. Now we see how many children after it also want
     // to be wrapped in an anonymous flex/grid item.
     FCItemIterator endIter(iter); // iterator to find the end of the group
-    endIter.SkipItemsThatNeedAnonFlexOrGridItem(aState, containerType,
-                                                isWebkitBox);
+    endIter.SkipItemsThatNeedAnonFlexOrGridItem(aState, isWebkitBox);
 
     NS_ASSERTION(iter != endIter,
                  "Should've had at least one wrappable child to seek past");
 
     // Now, we create the anonymous flex or grid item to contain the children
     // between |iter| and |endIter|.
-    nsIAtom* pseudoType = containerType == nsGkAtoms::flexContainerFrame ?
+    nsIAtom* pseudoType = (aParentFrame->GetType() == nsGkAtoms::flexContainerFrame) ?
       nsCSSAnonBoxes::anonymousFlexItem : nsCSSAnonBoxes::anonymousGridItem;
     nsStyleContext* parentStyle = aParentFrame->StyleContext();
     nsIContent* parentContent = aParentFrame->GetContent();
@@ -12171,11 +12165,9 @@ nsCSSFrameConstructor::WipeContainingBlock(nsFrameConstructorState& aState,
 
     // Check if we're adding to-be-wrapped content right *after* an existing
     // anonymous flex or grid item (which would need to absorb this content).
-    nsIAtom* containerType = aFrame->GetType();
     const bool isWebkitBox = nsFlexContainerFrame::IsLegacyBox(aFrame);
     if (aPrevSibling && IsAnonymousFlexOrGridItem(aPrevSibling) &&
-        iter.item().NeedsAnonFlexOrGridItem(aState, containerType,
-                                            isWebkitBox)) {
+        iter.item().NeedsAnonFlexOrGridItem(aState, isWebkitBox)) {
       RecreateFramesForContent(aFrame->GetContent(), true,
                                REMOVE_FOR_RECONSTRUCTION, nullptr);
       return true;
@@ -12187,8 +12179,7 @@ nsCSSFrameConstructor::WipeContainingBlock(nsFrameConstructorState& aState,
       // Jump to the last entry in the list
       iter.SetToEnd();
       iter.Prev();
-      if (iter.item().NeedsAnonFlexOrGridItem(aState, containerType,
-                                              isWebkitBox)) {
+      if (iter.item().NeedsAnonFlexOrGridItem(aState, isWebkitBox)) {
         RecreateFramesForContent(aFrame->GetContent(), true,
                                  REMOVE_FOR_RECONSTRUCTION, nullptr);
         return true;
@@ -12216,7 +12207,6 @@ nsCSSFrameConstructor::WipeContainingBlock(nsFrameConstructorState& aState,
     nsIFrame* containerFrame = aFrame->GetParent();
     const bool isWebkitBox = nsFlexContainerFrame::IsLegacyBox(containerFrame);
     if (!iter.SkipItemsThatNeedAnonFlexOrGridItem(aState,
-                                                  containerFrame->GetType(),
                                                   isWebkitBox)) {
       // We hit something that _doesn't_ need an anonymous flex item!
       // Rebuild the flex container to bust it out.
@@ -12675,7 +12665,6 @@ Iterator::SkipItemsNotWantingParentType(ParentType aParentType)
 bool
 nsCSSFrameConstructor::FrameConstructionItem::
   NeedsAnonFlexOrGridItem(const nsFrameConstructorState& aState,
-                          nsIAtom* aContainerType,
                           bool aIsWebkitBox)
 {
   if (mFCData->mBits & FCDATA_IS_LINE_PARTICIPANT) {
@@ -12696,12 +12685,10 @@ inline bool
 nsCSSFrameConstructor::FrameConstructionItemList::
 Iterator::SkipItemsThatNeedAnonFlexOrGridItem(
   const nsFrameConstructorState& aState,
-  nsIAtom* aContainerType,
   bool aIsWebkitBox)
 {
   NS_PRECONDITION(!IsDone(), "Shouldn't be done yet");
-  while (item().NeedsAnonFlexOrGridItem(aState, aContainerType,
-                                        aIsWebkitBox)) {
+  while (item().NeedsAnonFlexOrGridItem(aState, aIsWebkitBox)) {
     Next();
     if (IsDone()) {
       return true;
@@ -12714,12 +12701,10 @@ inline bool
 nsCSSFrameConstructor::FrameConstructionItemList::
 Iterator::SkipItemsThatDontNeedAnonFlexOrGridItem(
   const nsFrameConstructorState& aState,
-  nsIAtom* aContainerType,
   bool aIsWebkitBox)
 {
   NS_PRECONDITION(!IsDone(), "Shouldn't be done yet");
-  while (!(item().NeedsAnonFlexOrGridItem(aState, aContainerType,
-                                          aIsWebkitBox))) {
+  while (!(item().NeedsAnonFlexOrGridItem(aState, aIsWebkitBox))) {
     Next();
     if (IsDone()) {
       return true;
diff --git a/layout/base/nsCSSFrameConstructor.h b/layout/base/nsCSSFrameConstructor.h
index 346d73f13c28..7d1b8d42fffe 100644
--- a/layout/base/nsCSSFrameConstructor.h
+++ b/layout/base/nsCSSFrameConstructor.h
@@ -956,14 +956,14 @@ private:
       // Return whether the iterator is done after doing that.
       // The iterator must not be done when this is called.
       inline bool SkipItemsThatNeedAnonFlexOrGridItem(
-        const nsFrameConstructorState& aState, nsIAtom* aContainerType,
+        const nsFrameConstructorState& aState,
         bool aIsWebkitBox);
 
       // Skip to the first frame that is a non-replaced inline or is
       // positioned.  Return whether the iterator is done after doing that.
       // The iterator must not be done when this is called.
       inline bool SkipItemsThatDontNeedAnonFlexOrGridItem(
-        const nsFrameConstructorState& aState, nsIAtom* aContainerType,
+        const nsFrameConstructorState& aState,
         bool aIsWebkitBox);
 
       // Skip over all items that do not want a ruby parent.  Return whether
@@ -1099,7 +1099,6 @@ private:
     // but we use different rules for what gets wrapped. The aIsWebkitBox
     // parameter here tells us whether to use those different rules.)
     bool NeedsAnonFlexOrGridItem(const nsFrameConstructorState& aState,
-                                 nsIAtom* aContainerType,
                                  bool aIsWebkitBox);
 
     // Don't call this unless the frametree really depends on the answer!