--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -919,29 +919,27 @@ public:
    * Function to add a new frame to the right frame list.  This MUST be called
    * on frames before their children have been processed if the frames might
    * conceivably be out-of-flow; otherwise cleanup in error cases won't work
    * right.  Also, this MUST be called on frames after they have been
    * initialized.
    * @param aNewFrame the frame to add
    * @param aFrameItems the list to add in-flow frames to
    * @param aContent the content pointer for aNewFrame
-   * @param aStyleContext the style context resolved for aContent
    * @param aParentFrame the parent frame for the content if it were in-flow
    * @param aCanBePositioned pass false if the frame isn't allowed to be
    *        positioned
    * @param aCanBeFloated pass false if the frame isn't allowed to be
    *        floated
    * @param aIsOutOfFlowPopup pass true if the frame is an out-of-flow popup
    *        (XUL-only)
    */
   void AddChild(nsIFrame* aNewFrame,
                 nsFrameItems& aFrameItems,
                 nsIContent* aContent,
-                nsStyleContext* aStyleContext,
                 nsContainerFrame* aParentFrame,
                 bool aCanBePositioned = true,
                 bool aCanBeFloated = true,
                 bool aIsOutOfFlowPopup = false,
                 bool aInsertAfter = false,
                 nsIFrame* aInsertAfterFrame = nullptr);
 
   /**
@@ -1315,17 +1313,16 @@ nsFrameConstructorState::ConstructBackdr
 
   frameItems->AddChild(backdropFrame);
 }
 
 void
 nsFrameConstructorState::AddChild(nsIFrame* aNewFrame,
                                   nsFrameItems& aFrameItems,
                                   nsIContent* aContent,
-                                  nsStyleContext* aStyleContext,
                                   nsContainerFrame* aParentFrame,
                                   bool aCanBePositioned,
                                   bool aCanBeFloated,
                                   bool aIsOutOfFlowPopup,
                                   bool aInsertAfter,
                                   nsIFrame* aInsertAfterFrame)
 {
   NS_PRECONDITION(!aNewFrame->GetNextSibling(), "Shouldn't happen");
@@ -2207,17 +2204,17 @@ nsCSSFrameConstructor::ConstructTable(ns
     innerFrame = NS_NewTableFrame(mPresShell, styleContext);
 
   InitAndRestoreFrame(aState, content, newFrame, innerFrame);
   innerFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);
 
   // Put the newly created frames into the right child list
   SetInitialSingleChild(newFrame, innerFrame);
 
-  aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame);
+  aState.AddChild(newFrame, aFrameItems, content, aParentFrame);
 
   if (!mRootElementFrame) {
     // The frame we're constructing will be the root element frame.
     // Set mRootElementFrame before processing children.
     mRootElementFrame = newFrame;
   }
 
   nsFrameItems childItems;
@@ -3222,18 +3219,17 @@ nsCSSFrameConstructor::ConstructSelectFr
     aState.mFrameState = nullptr;
     // Initialize the combobox frame
     InitAndRestoreFrame(aState, content,
                         aState.GetGeometricParent(aStyleDisplay, aParentFrame),
                         comboboxFrame);
 
     comboboxFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);
 
-    aState.AddChild(comboboxFrame, aFrameItems, content, styleContext,
-                    aParentFrame);
+    aState.AddChild(comboboxFrame, aFrameItems, content, aParentFrame);
 
     // Resolve pseudo element style for the dropdown list
     RefPtr<nsStyleContext> listStyle;
     listStyle = mPresShell->StyleSet()->
       ResolveInheritingAnonymousBoxStyle(nsCSSAnonBoxes::dropDownList,
                                          styleContext);
 
     // Create a listbox
@@ -3347,18 +3343,17 @@ nsCSSFrameConstructor::InitializeSelectF
 
   // We don't call InitAndRestoreFrame for scrollFrame because we can only
   // restore the frame state after its parts have been created (in particular,
   // the scrollable view). So we have to split Init and Restore.
 
   scrollFrame->Init(aContent, geometricParent, nullptr);
 
   if (!aBuildCombobox) {
-    aState.AddChild(scrollFrame, aFrameItems, aContent,
-                    aStyleContext, aParentFrame);
+    aState.AddChild(scrollFrame, aFrameItems, aContent, aParentFrame);
   }
 
   BuildScrollFrame(aState, aContent, aStyleContext, scrolledFrame,
                    geometricParent, scrollFrame);
 
   if (aState.mFrameState) {
     // Restore frame state for the scroll frame
     RestoreFrameStateFor(scrollFrame, aState.mFrameState);
@@ -3457,17 +3452,17 @@ nsCSSFrameConstructor::ConstructFieldSet
       } else {
         InitAndRestoreFrame(aState, content, parent, contentFrame);
         contentFrameTop = contentFrame;
       }
       break;
     }
   }
 
-  aState.AddChild(fieldsetFrame, aFrameItems, content, styleContext, aParentFrame);
+  aState.AddChild(fieldsetFrame, aFrameItems, content, aParentFrame);
 
   // Process children
   nsFrameConstructorSaveState absoluteSaveState;
   nsFrameItems                childItems;
 
   contentFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
   if (absPosContainer) {
     aState.PushAbsoluteContainingBlock(contentFrame, absPosContainer, absoluteSaveState);
@@ -4122,18 +4117,18 @@ nsCSSFrameConstructor::ConstructFrameFro
         maybeAbsoluteContainingBlockStyleFrame = outerFrame;
         innerFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
       }
 
       // Our kids should go into the innerFrame.
       newFrame = innerFrame;
     }
 
-    aState.AddChild(frameToAddToList, aFrameItems, content, styleContext,
-                    aParentFrame, allowOutOfFlow, allowOutOfFlow, isPopup);
+    aState.AddChild(frameToAddToList, aFrameItems, content, aParentFrame,
+                    allowOutOfFlow, allowOutOfFlow, isPopup);
 
     nsContainerFrame* newFrameAsContainer = do_QueryFrame(newFrame);
     if (newFrameAsContainer) {
 #ifdef MOZ_XUL
       // Icky XUL stuff, sadly
 
       if (aItem.mIsRootPopupgroup) {
         NS_ASSERTION(nsIRootBox::GetRootBox(mPresShell) &&
@@ -5033,17 +5028,17 @@ nsCSSFrameConstructor::ConstructScrollab
                                false, newFrame);
 
   // Create our block frame
   // pass a temporary stylecontext, the correct one will be set later
   nsContainerFrame* scrolledFrame = aConstructor(mPresShell, styleContext);
 
   // Make sure to AddChild before we call ConstructBlock so that we
   // end up before our descendants in fixed-pos lists as needed.
-  aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame);
+  aState.AddChild(newFrame, aFrameItems, content, aParentFrame);
 
   nsFrameItems blockItem;
   ConstructBlock(aState, content, newFrame, newFrame, scrolledContentStyle,
                  &scrolledFrame, blockItem,
                  aDisplay->IsAbsPosContainingBlock(newFrame) ? newFrame : nullptr,
                  aItem.mPendingBinding);
 
   MOZ_ASSERT(blockItem.OnlyChild() == scrolledFrame,
@@ -5411,17 +5406,17 @@ nsCSSFrameConstructor::ConstructFrameWit
   // Create the anonymous inner wrapper frame
   nsContainerFrame* innerFrame = aInnerConstructor(mPresShell, scForAnon);
 
   InitAndRestoreFrame(aState, content, newFrame, innerFrame);
 
   // Put the newly created frames into the right child list
   SetInitialSingleChild(newFrame, innerFrame);
 
-  aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame,
+  aState.AddChild(newFrame, aFrameItems, content, aParentFrame,
                   aCandidateRootFrame, aCandidateRootFrame);
 
   if (!mRootElementFrame && aCandidateRootFrame) {
     // The frame we're constructing will be the root element frame.
     // Set mRootElementFrame before processing children.
     mRootElementFrame = newFrame;
   }
 
@@ -11542,19 +11537,18 @@ nsCSSFrameConstructor::CreateFloatingLet
   // Put the new float before any of the floats in the block we're doing
   // first-letter for, that is, before any floats whose parent is
   // containingBlock.
   nsFrameList::FrameLinkEnumerator link(aState.mFloatedItems);
   while (!link.AtEnd() && link.NextFrame()->GetParent() != containingBlock) {
     link.Next();
   }
 
-  aState.AddChild(letterFrame, aResult, letterContent, aStyleContext,
-                  aParentFrame, false, true, false, true,
-                  link.PrevFrame());
+  aState.AddChild(letterFrame, aResult, letterContent, aParentFrame,
+                  false, true, false, true, link.PrevFrame());
 
   if (nextTextFrame) {
     aResult.AddChild(nextTextFrame);
   }
 
   return letterFrame;
 }
 
@@ -12106,17 +12100,17 @@ nsCSSFrameConstructor::ConstructBlock(ns
     }
 
     SetInitialSingleChild(columnSetFrame, blockFrame);
   }
 
   blockFrame->SetStyleContextWithoutNotification(blockStyle);
   InitAndRestoreFrame(aState, aContent, parent, blockFrame);
 
-  aState.AddChild(*aNewFrame, aFrameItems, aContent, aStyleContext,
+  aState.AddChild(*aNewFrame, aFrameItems, aContent,
                   aContentParentFrame ? aContentParentFrame :
                                         aParentFrame);
   if (!mRootElementFrame) {
     // The frame we're constructing will be the root element frame.
     // Set mRootElementFrame before processing children.
     mRootElementFrame = *aNewFrame;
   }
 
@@ -12248,17 +12242,17 @@ nsCSSFrameConstructor::ConstructInline(n
   if (aItem.mIsAllInline || firstBlockEnumerator.AtEnd()) {
     // This part is easy.  We either already know we have no non-inline kids,
     // or haven't found any when constructing actual frames (the latter can
     // happen only if out-of-flows that we thought had no containing block
     // acquired one when ancestor inline frames and {ib} splits got
     // constructed).  Just put all the kids into the single inline frame and
     // bail.
     newFrame->SetInitialChildList(kPrincipalList, childItems);
-    aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame);
+    aState.AddChild(newFrame, aFrameItems, content, aParentFrame);
     return newFrame;
   }
 
   // This inline frame contains several types of children. Therefore this frame
   // has to be chopped into several pieces, as described above.
 
   // Grab the first inline's kids
   nsFrameList firstInlineKids = childItems.ExtractHead(firstBlockEnumerator);