--- a/dom/base/nsGkAtomList.h
+++ b/dom/base/nsGkAtomList.h
@@ -1998,17 +1998,16 @@ GK_ATOM(rubyBaseContainerFrame, "RubyBas
 GK_ATOM(rubyBaseFrame, "RubyBaseFrame")
 GK_ATOM(rubyFrame, "RubyFrame")
 GK_ATOM(rubyTextContainerFrame, "RubyTextContainerFrame")
 GK_ATOM(rubyTextFrame, "RubyTextFrame")
 GK_ATOM(scrollFrame, "ScrollFrame")
 GK_ATOM(scrollbarFrame, "ScrollbarFrame")
 GK_ATOM(sequenceFrame, "SequenceFrame")
 GK_ATOM(sliderFrame, "sliderFrame")
-GK_ATOM(summaryFrame, "SummaryFrame")
 GK_ATOM(tableCellFrame, "TableCellFrame")
 GK_ATOM(tableColFrame, "TableColFrame")
 GK_ATOM(tableColGroupFrame, "TableColGroupFrame")
 GK_ATOM(tableFrame, "TableFrame")
 GK_ATOM(tableOuterFrame, "TableOuterFrame")
 GK_ATOM(tableRowGroupFrame, "TableRowGroupFrame")
 GK_ATOM(tableRowFrame, "TableRowFrame")
 GK_ATOM(textInputFrame,"TextInputFrame")

--- a/layout/base/nsCSSFrameConstructor.cpp
+++ b/layout/base/nsCSSFrameConstructor.cpp
@@ -91,17 +91,16 @@
 #include "nsGfxScrollFrame.h"
 #include "nsPageFrame.h"
 #include "nsSimplePageSequenceFrame.h"
 #include "nsTableOuterFrame.h"
 #include "nsIScrollableFrame.h"
 #include "nsBackdropFrame.h"
 #include "nsTransitionManager.h"
 #include "DetailsFrame.h"
-#include "SummaryFrame.h"
 
 #ifdef MOZ_XUL
 #include "nsIRootBox.h"
 #endif
 #ifdef ACCESSIBILITY
 #include "nsAccessibilityService.h"
 #endif
 
@@ -3619,20 +3618,17 @@ nsCSSFrameConstructor::FindHTMLData(Elem
       FCDATA_WITH_WRAPPING_BLOCK(FCDATA_ALLOW_BLOCK_STYLES,
                                  NS_NewHTMLButtonControlFrame,
                                  nsCSSAnonBoxes::buttonContent) },
     SIMPLE_TAG_CHAIN(canvas, nsCSSFrameConstructor::FindCanvasData),
     SIMPLE_TAG_CREATE(video, NS_NewHTMLVideoFrame),
     SIMPLE_TAG_CREATE(audio, NS_NewHTMLVideoFrame),
     SIMPLE_TAG_CREATE(progress, NS_NewProgressFrame),
     SIMPLE_TAG_CREATE(meter, NS_NewMeterFrame),
-    COMPLEX_TAG_CREATE(details, &nsCSSFrameConstructor::ConstructDetailsFrame),
-    { &nsGkAtoms::summary,
-      FCDATA_DECL(FCDATA_ALLOW_BLOCK_STYLES | FCDATA_MAY_NEED_SCROLLFRAME,
-                  NS_NewSummaryFrame) }
+    COMPLEX_TAG_CREATE(details, &nsCSSFrameConstructor::ConstructDetailsFrame)
   };
 
   return FindDataByTag(aTag, aElement, aStyleContext, sHTMLData,
                        ArrayLength(sHTMLData));
 }
 
 /* static */
 const nsCSSFrameConstructor::FrameConstructionData*
@@ -8938,19 +8934,16 @@ nsCSSFrameConstructor::CreateContinuingF
     newFrame = NS_NewRubyBaseContainerFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
   } else if (nsGkAtoms::rubyTextContainerFrame == frameType) {
     newFrame = NS_NewRubyTextContainerFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
   } else if (nsGkAtoms::detailsFrame == frameType) {
     newFrame = NS_NewDetailsFrame(shell, styleContext);
     newFrame->Init(content, aParentFrame, aFrame);
-  } else if (nsGkAtoms::summaryFrame == frameType) {
-    newFrame = NS_NewSummaryFrame(shell, styleContext);
-    newFrame->Init(content, aParentFrame, aFrame);
   } else {
     NS_RUNTIMEABORT("unexpected frame type");
   }
 
   // Init() set newFrame to be a fluid continuation of aFrame.
   // If we want a non-fluid continuation, we need to call SetPrevContinuation()
   // to reset NS_FRAME_IS_FLUID_CONTINUATION.
   if (!aIsFluid) {
@@ -9269,25 +9262,30 @@ nsCSSFrameConstructor::MaybeRecreateCont
       aFrame->GetParent()->GetType() == nsGkAtoms::fieldSetFrame) {
     // When we remove the legend for a fieldset, we should reframe
     // the fieldset to ensure another legend is used, if there is one
     *aResult = RecreateFramesForContent(aFrame->GetParent()->GetContent(), false,
                                         aFlags, aDestroyedFramesFor);
     return true;
   }
 
-  if (insertionFrame && insertionFrame->GetType() == nsGkAtoms::summaryFrame &&
+  if (insertionFrame &&
       aFrame->GetParent()->GetType() == nsGkAtoms::detailsFrame) {
-    // When removing a summary frame, we should reframe the parent details frame
-    // to ensure that another summary is used or the default summary is
-    // generated.
-    *aResult = RecreateFramesForContent(aFrame->GetParent()->GetContent(),
-                                        false, REMOVE_FOR_RECONSTRUCTION,
-                                        aDestroyedFramesFor);
-    return true;
+    HTMLSummaryElement* summary =
+      HTMLSummaryElement::FromContent(insertionFrame->GetContent());
+
+    if (summary && summary->IsMainSummary()) {
+      // When removing a summary, we should reframe the parent details frame to
+      // ensure that another summary is used or the default summary is
+      // generated.
+      *aResult = RecreateFramesForContent(aFrame->GetParent()->GetContent(),
+                                          false, REMOVE_FOR_RECONSTRUCTION,
+                                          aDestroyedFramesFor);
+      return true;
+    }
   }
 
   // Now check for possibly needing to reconstruct due to a pseudo parent
   nsIFrame* inFlowFrame =
     (aFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW) ?
       GetPlaceholderFrameFor(aFrame) : aFrame;
   MOZ_ASSERT(inFlowFrame, "How did that happen?");
   MOZ_ASSERT(inFlowFrame == inFlowFrame->FirstContinuation(),

--- a/layout/generic/DetailsFrame.cpp
+++ b/layout/generic/DetailsFrame.cpp
@@ -49,19 +49,20 @@ DetailsFrame::SetInitialChildList(ChildL
   if (aListID == kPrincipalList) {
     HTMLDetailsElement* details = HTMLDetailsElement::FromContent(GetContent());
     bool isOpen = details->Open();
 
     if (isOpen) {
       // If details is open, the first summary needs to be rendered as if it is
       // the first child.
       for (nsIFrame* child : aChildList) {
-        auto* realFrame = nsPlaceholderFrame::GetRealFrameFor(child);
-        auto* cif = realFrame->GetContentInsertionFrame();
-        if (cif && cif->GetType() == nsGkAtoms::summaryFrame) {
+        HTMLSummaryElement* summary =
+          HTMLSummaryElement::FromContent(child->GetContent());
+
+        if (summary && summary->IsMainSummary()) {
           // Take out the first summary frame and insert it to the beginning of
           // the list.
           aChildList.RemoveFrame(child);
           aChildList.InsertFrame(nullptr, nullptr, child);
           break;
         }
       }
     }

deleted file mode 100644
--- a/layout/generic/SummaryFrame.cpp
+++ /dev/null
@@ -1,38 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "SummaryFrame.h"
-
-#include "mozilla/Attributes.h"
-#include "mozilla/dom/HTMLSummaryElement.h"
-
-NS_IMPL_FRAMEARENA_HELPERS(SummaryFrame)
-
-SummaryFrame*
-NS_NewSummaryFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
-{
-  return new (aPresShell) SummaryFrame(aContext);
-}
-
-SummaryFrame::SummaryFrame(nsStyleContext* aContext)
-  : nsBlockFrame(aContext)
-{
-}
-
-SummaryFrame::~SummaryFrame()
-{
-}
-
-nsIAtom*
-SummaryFrame::GetType() const
-{
-  return nsGkAtoms::summaryFrame;
-}
-
-void
-SummaryFrame::SetInitialChildList(ChildListID aListID, nsFrameList& aChildList)
-{
-  nsBlockFrame::SetInitialChildList(aListID, aChildList);
-}

deleted file mode 100644
--- a/layout/generic/SummaryFrame.h
+++ /dev/null
@@ -1,38 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef SummaryFrame_h
-#define SummaryFrame_h
-
-#include "nsBlockFrame.h"
-
-class nsStyleContext;
-
-// SummaryFrame is generated by HTMLSummaryElement.
-//
-class SummaryFrame final : public nsBlockFrame
-{
-public:
-  NS_DECL_FRAMEARENA_HELPERS
-
-  explicit SummaryFrame(nsStyleContext* aContext);
-
-  virtual ~SummaryFrame();
-
-  nsIAtom* GetType() const override;
-
-#ifdef DEBUG_FRAME_DUMP
-  nsresult GetFrameName(nsAString& aResult) const override
-  {
-    return MakeFrameName(NS_LITERAL_STRING("Summary"), aResult);
-  }
-#endif
-
-  void SetInitialChildList(ChildListID aListID,
-                           nsFrameList& aChildList) override;
-};
-
-#endif // SummaryFrame_h

--- a/layout/generic/moz.build
+++ b/layout/generic/moz.build
@@ -165,17 +165,16 @@ UNIFIED_SOURCES += [
     'nsTextRunTransformations.cpp',
     'nsVideoFrame.cpp',
     'nsViewportFrame.cpp',
     'RubyUtils.cpp',
     'ScrollbarActivity.cpp',
     'ScrollSnap.cpp',
     'ScrollVelocityQueue.cpp',
     'StickyScrollContainer.cpp',
-    'SummaryFrame.cpp',
     'TextOverflow.cpp',
 ]
 
 # nsLineLayout.cpp needs to be built separately because it uses plarena.h.
 # nsPluginFrame.cpp needs to be built separately because of name clashes in the OS X headers.
 SOURCES += [
     'nsLineLayout.cpp',
     'nsPluginFrame.cpp',

--- a/layout/generic/nsFrameIdList.h
+++ b/layout/generic/nsFrameIdList.h
@@ -171,10 +171,9 @@ FRAME_ID(nsTextBoxFrame)
 FRAME_ID(nsTextControlFrame)
 FRAME_ID(nsTextFrame)
 FRAME_ID(nsTitleBarFrame)
 FRAME_ID(nsTreeBodyFrame)
 FRAME_ID(nsTreeColFrame)
 FRAME_ID(nsVideoFrame)
 FRAME_ID(nsXULLabelFrame)
 FRAME_ID(nsXULScrollFrame)
-FRAME_ID(SummaryFrame)
 FRAME_ID(ViewportFrame)

--- a/layout/generic/nsHTMLParts.h
+++ b/layout/generic/nsHTMLParts.h
@@ -173,19 +173,16 @@ nsIFrame*
 NS_NewMeterFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewRangeFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 nsIFrame*
 NS_NewNumberControlFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 class DetailsFrame;
 DetailsFrame*
 NS_NewDetailsFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
-class SummaryFrame;
-SummaryFrame*
-NS_NewSummaryFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 
 // Table frame factories
 class nsTableOuterFrame;
 nsTableOuterFrame*
 NS_NewTableOuterFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
 class nsTableFrame;
 nsTableFrame*
 NS_NewTableFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);