Bug 1308080 - Make <details> use a shadow tree as per spec. r=TYLin,smaug

The behavior changes match WebKit and Blink. I can look into upstreaming
some of these to WPT.

Differential Revision: https://phabricator.services.mozilla.com/D34754

dom/base/ShadowRoot.cpp

@@ -13,7 +13,9 @@
 #include "nsWindowSizes.h"
 #include "mozilla/dom/DirectionalityUtils.h"
 #include "mozilla/dom/Element.h"
+#include "mozilla/dom/HTMLDetailsElement.h"
 #include "mozilla/dom/HTMLSlotElement.h"
+#include "mozilla/dom/HTMLSummaryElement.h"
 #include "mozilla/dom/Text.h"
 #include "mozilla/dom/TreeOrderedArrayInlines.h"
 #include "mozilla/EventDispatcher.h"
@@ -57,6 +59,7 @@ ShadowRoot::ShadowRoot(Element* aElement, ShadowRootMode aMode,
       mDelegatesFocus(aDelegatesFocus),
       mSlotAssignment(aSlotAssignment),
       mIsUAWidget(false),
+      mIsDetailsShadowTree(aElement->IsHTMLElement(nsGkAtoms::details)),
       mIsAvailableToElementInternals(false) {
   SetHost(aElement);
 
@@ -251,9 +254,7 @@ void ShadowRoot::AddSlot(HTMLSlotElement* aSlot) {
       for (nsIContent* child = GetHost()->GetFirstChild(); child;
            child = child->GetNextSibling()) {
         nsAutoString slotName;
-        if (auto* element = Element::FromNode(*child)) {
-          element->GetAttr(nsGkAtoms::slot, slotName);
-        }
+        GetSlotNameFor(*child, slotName);
         if (!child->IsSlotable() || !slotName.Equals(name)) {
           continue;
         }
@@ -581,6 +582,24 @@ void ShadowRoot::GetEventTargetParent(EventChainPreVisitor& aVisitor) {
   }
 }
 
+void ShadowRoot::GetSlotNameFor(const nsIContent& aContent,
+                                nsAString& aName) const {
+  if (mIsDetailsShadowTree) {
+    const auto* summary = HTMLSummaryElement::FromNode(aContent);
+    if (summary && summary->IsMainSummary()) {
+      aName.AssignLiteral("internal-main-summary");
+    }
+    // Otherwise use the default slot.
+    return;
+  }
+
+  // Note that if slot attribute is missing, assign it to the first default
+  // slot, if exists.
+  if (const Element* element = Element::FromNode(aContent)) {
+    element->GetAttr(nsGkAtoms::slot, aName);
+  }
+}
+
 ShadowRoot::SlotInsertionPoint ShadowRoot::SlotInsertionPointFor(
     nsIContent& aContent) {
   HTMLSlotElement* slot = nullptr;
@@ -592,11 +611,7 @@ ShadowRoot::SlotInsertionPoint ShadowRoot::SlotInsertionPointFor(
     }
   } else {
     nsAutoString slotName;
-    // Note that if slot attribute is missing, assign it to the first default
-    // slot, if exists.
-    if (Element* element = Element::FromNode(aContent)) {
-      element->GetAttr(nsGkAtoms::slot, slotName);
-    }
+    GetSlotNameFor(aContent, slotName);
 
     SlotArray* slots = mSlotMap.Get(slotName);
     if (!slots) {
@@ -701,6 +716,29 @@ void ShadowRoot::MaybeReassignContent(nsIContent& aElementOrText) {
   }
 }
 
+void ShadowRoot::MaybeReassignMainSummary(SummaryChangeReason aReason) {
+  MOZ_ASSERT(mIsDetailsShadowTree);
+  if (aReason == SummaryChangeReason::Insertion) {
+    // We've inserted a summary element, may need to remove the existing one.
+    SlotArray* array = mSlotMap.Get(u"internal-main-summary"_ns);
+    MOZ_RELEASE_ASSERT(array && (*array)->Length() == 1);
+    HTMLSlotElement* slot = (*array)->ElementAt(0);
+    auto* summary = HTMLSummaryElement::FromNodeOrNull(
+        slot->AssignedNodes().SafeElementAt(0));
+    if (summary) {
+      MaybeReassignContent(*summary);
+    }
+  } else if (MOZ_LIKELY(GetHost())) {
+    // We need to null-check GetHost() in case we're unlinking already.
+    auto* details = HTMLDetailsElement::FromNode(Host());
+    MOZ_DIAGNOSTIC_ASSERT(details);
+    // We've removed a summary element, we may need to assign the new one.
+    if (HTMLSummaryElement* newMainSummary = details->GetFirstSummary()) {
+      MaybeReassignContent(*newMainSummary);
+    }
+  }
+}
+
 Element* ShadowRoot::GetActiveElement() {
   return GetRetargetedFocusedElement();
 }
@@ -763,6 +801,10 @@ void ShadowRoot::MaybeUnslotHostChild(nsIContent& aChild) {
 
   slot->RemoveAssignedNode(aChild);
   slot->EnqueueSlotChangeEvent();
+
+  if (mIsDetailsShadowTree && aChild.IsHTMLElement(nsGkAtoms::summary)) {
+    MaybeReassignMainSummary(SummaryChangeReason::Deletion);
+  }
 }
 
 Element* ShadowRoot::GetFirstFocusable(bool aWithMouse) const {
@@ -809,6 +851,10 @@ void ShadowRoot::MaybeSlotHostChild(nsIContent& aChild) {
     return;
   }
 
+  if (mIsDetailsShadowTree && aChild.IsHTMLElement(nsGkAtoms::summary)) {
+    MaybeReassignMainSummary(SummaryChangeReason::Insertion);
+  }
+
   SlotInsertionPoint assignment = SlotInsertionPointFor(aChild);
   if (!assignment.mSlot) {
     return;

dom/base/ShadowRoot.h

@@ -22,7 +22,6 @@
 
 class nsAtom;
 class nsIContent;
-class nsXBLPrototypeBinding;
 
 namespace mozilla {
 
@@ -159,6 +158,21 @@ class ShadowRoot final : public DocumentFragment,
    */
   SlotInsertionPoint SlotInsertionPointFor(nsIContent&);
 
+  /**
+   * Returns the effective slot name for a given slottable. In most cases, this
+   * is just the value of the slot attribute, if any, or the empty string, but
+   * this also deals with the <details> shadow tree specially.
+   */
+  void GetSlotNameFor(const nsIContent&, nsAString&) const;
+
+  /**
+   * Re-assign the current main summary if it has changed.
+   *
+   * Must be called only if mIsDetailsShadowTree is true.
+   */
+  enum class SummaryChangeReason { Deletion, Insertion };
+  void MaybeReassignMainSummary(SummaryChangeReason);
+
  public:
   void AddSlot(HTMLSlotElement* aSlot);
   void RemoveSlot(HTMLSlotElement* aSlot);
@@ -297,6 +311,9 @@ class ShadowRoot final : public DocumentFragment,
 
   bool mIsUAWidget : 1;
 
+  // Whether this is the <details> internal shadow tree.
+  bool mIsDetailsShadowTree : 1;
+
   // https://dom.spec.whatwg.org/#shadowroot-available-to-element-internals
   bool mIsAvailableToElementInternals : 1;
 

dom/base/nsContentUtils.cpp

@@ -10721,7 +10721,7 @@ nsContentUtils::GetSubresourceCacheValidationInfo(nsIRequest* aRequest,
         aURI->SchemeIs("moz-extension")) {
       return true;
     }
-    if (dom::IsChromeURI(aURI)) {
+    if (aURI->SchemeIs("chrome") || aURI->SchemeIs("resource")) {
       return !StaticPrefs::nglayout_debug_disable_xul_cache();
     }
     return false;

dom/html/HTMLDetailsElement.cpp

@@ -7,6 +7,11 @@
 #include "mozilla/dom/HTMLDetailsElement.h"
 
 #include "mozilla/dom/HTMLDetailsElementBinding.h"
+#include "mozilla/dom/HTMLSummaryElement.h"
+#include "mozilla/dom/ShadowRoot.h"
+#include "mozilla/ScopeExit.h"
+#include "nsContentUtils.h"
+#include "nsTextNode.h"
 
 NS_IMPL_NS_NEW_HTML_ELEMENT(Details)
 
@@ -16,33 +21,31 @@ HTMLDetailsElement::~HTMLDetailsElement() = default;
 
 NS_IMPL_ELEMENT_CLONE(HTMLDetailsElement)
 
-nsIContent* HTMLDetailsElement::GetFirstSummary() const {
+HTMLDetailsElement::HTMLDetailsElement(already_AddRefed<NodeInfo>&& aNodeInfo)
+    : nsGenericHTMLElement(std::move(aNodeInfo)) {
+  SetupShadowTree();
+}
+
+HTMLSummaryElement* HTMLDetailsElement::GetFirstSummary() const {
   // XXX: Bug 1245032: Might want to cache the first summary element.
   for (nsIContent* child = nsINode::GetFirstChild(); child;
        child = child->GetNextSibling()) {
-    if (child->IsHTMLElement(nsGkAtoms::summary)) {
-      return child;
+    if (auto* summary = HTMLSummaryElement::FromNode(child)) {
+      return summary;
     }
   }
   return nullptr;
 }
 
-nsChangeHint HTMLDetailsElement::GetAttributeChangeHint(
-    const nsAtom* aAttribute, int32_t aModType) const {
-  nsChangeHint hint =
-      nsGenericHTMLElement::GetAttributeChangeHint(aAttribute, aModType);
-  if (aAttribute == nsGkAtoms::open) {
-    hint |= nsChangeHint_ReconstructFrame;
-  }
-  return hint;
-}
-
-nsresult HTMLDetailsElement::BeforeSetAttr(int32_t aNameSpaceID, nsAtom* aName,
-                                           const nsAttrValueOrString* aValue,
-                                           bool aNotify) {
+nsresult HTMLDetailsElement::AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName,
+                                          const nsAttrValue* aValue,
+                                          const nsAttrValue* aOldValue,
+                                          nsIPrincipal* aMaybeScriptedPrincipal,
+                                          bool aNotify) {
   if (aNameSpaceID == kNameSpaceID_None && aName == nsGkAtoms::open) {
-    bool setOpen = aValue != nullptr;
-    if (Open() != setOpen) {
+    bool wasOpen = !!aOldValue;
+    bool isOpen = !!aValue;
+    if (wasOpen != isOpen) {
       if (mToggleEventDispatcher) {
         mToggleEventDispatcher->Cancel();
       }
@@ -54,8 +57,70 @@ nsresult HTMLDetailsElement::BeforeSetAttr(int32_t aNameSpaceID, nsAtom* aName,
     }
   }
 
-  return nsGenericHTMLElement::BeforeSetAttr(aNameSpaceID, aName, aValue,
-                                             aNotify);
+  return nsGenericHTMLElement::AfterSetAttr(
+      aNameSpaceID, aName, aValue, aOldValue, aMaybeScriptedPrincipal, aNotify);
+}
+
+void HTMLDetailsElement::SetupShadowTree() {
+  const bool kNotify = false;
+  AttachAndSetUAShadowRoot(NotifyUAWidgetSetup::No);
+  RefPtr<ShadowRoot> sr = GetShadowRoot();
+  if (NS_WARN_IF(!sr)) {
+    return;
+  }
+
+  nsNodeInfoManager* nim = OwnerDoc()->NodeInfoManager();
+  RefPtr<NodeInfo> slotNodeInfo = nim->GetNodeInfo(
+      nsGkAtoms::slot, nullptr, kNameSpaceID_XHTML, nsINode::ELEMENT_NODE);
+  {
+    RefPtr<NodeInfo> linkNodeInfo = nim->GetNodeInfo(
+        nsGkAtoms::link, nullptr, kNameSpaceID_XHTML, nsINode::ELEMENT_NODE);
+    RefPtr<nsGenericHTMLElement> link =
+        NS_NewHTMLLinkElement(linkNodeInfo.forget());
+    if (NS_WARN_IF(!link)) {
+      return;
+    }
+    link->SetAttr(nsGkAtoms::rel, u"stylesheet"_ns, IgnoreErrors());
+    link->SetAttr(nsGkAtoms::href,
+                  u"resource://content-accessible/details.css"_ns,
+                  IgnoreErrors());
+    sr->AppendChildTo(link, kNotify, IgnoreErrors());
+  }
+  {
+    RefPtr<nsGenericHTMLElement> slot =
+        NS_NewHTMLSlotElement(do_AddRef(slotNodeInfo));
+    if (NS_WARN_IF(!slot)) {
+      return;
+    }
+    slot->SetAttr(kNameSpaceID_None, nsGkAtoms::name,
+                  u"internal-main-summary"_ns, kNotify);
+    sr->AppendChildTo(slot, kNotify, IgnoreErrors());
+
+    RefPtr<NodeInfo> summaryNodeInfo = nim->GetNodeInfo(
+        nsGkAtoms::summary, nullptr, kNameSpaceID_XHTML, nsINode::ELEMENT_NODE);
+    RefPtr<nsGenericHTMLElement> summary =
+        NS_NewHTMLSummaryElement(summaryNodeInfo.forget());
+    if (NS_WARN_IF(!summary)) {
+      return;
+    }
+
+    nsAutoString defaultSummaryText;
+    nsContentUtils::GetLocalizedString(nsContentUtils::eFORMS_PROPERTIES,
+                                       "DefaultSummary", defaultSummaryText);
+    RefPtr<nsTextNode> description = new (nim) nsTextNode(nim);
+    description->SetText(defaultSummaryText, kNotify);
+    summary->AppendChildTo(description, kNotify, IgnoreErrors());
+
+    slot->AppendChildTo(summary, kNotify, IgnoreErrors());
+  }
+  {
+    RefPtr<nsGenericHTMLElement> slot =
+        NS_NewHTMLSlotElement(slotNodeInfo.forget());
+    if (NS_WARN_IF(!slot)) {
+      return;
+    }
+    sr->AppendChildTo(slot, kNotify, IgnoreErrors());
+  }
 }
 
 void HTMLDetailsElement::AsyncEventRunning(AsyncEventDispatcher* aEvent) {

dom/html/HTMLDetailsElement.h

@@ -13,6 +13,8 @@
 
 namespace mozilla::dom {
 
+class HTMLSummaryElement;
+
 // HTMLDetailsElement implements the <details> tag, which is used as a
 // disclosure widget from which the user can obtain additional information or
 // controls. Please see the spec for more information.
@@ -22,22 +24,18 @@ class HTMLDetailsElement final : public nsGenericHTMLElement {
  public:
   using NodeInfo = mozilla::dom::NodeInfo;
 
-  explicit HTMLDetailsElement(already_AddRefed<NodeInfo>&& aNodeInfo)
-      : nsGenericHTMLElement(std::move(aNodeInfo)) {}
+  explicit HTMLDetailsElement(already_AddRefed<NodeInfo>&& aNodeInfo);
 
   NS_IMPL_FROMNODE_HTML_WITH_TAG(HTMLDetailsElement, details)
 
-  nsIContent* GetFirstSummary() const;
+  HTMLSummaryElement* GetFirstSummary() const;
 
   nsresult Clone(NodeInfo* aNodeInfo, nsINode** aResult) const override;
 
-  // Element
-  nsChangeHint GetAttributeChangeHint(const nsAtom* aAttribute,
-                                      int32_t aModType) const override;
-
-  nsresult BeforeSetAttr(int32_t aNameSpaceID, nsAtom* aName,
-                         const nsAttrValueOrString* aValue,
-                         bool aNotify) override;
+  nsresult AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName,
+                        const nsAttrValue* aValue, const nsAttrValue* aOldValue,
+                        nsIPrincipal* aMaybeScriptedPrincipal,
+                        bool aNotify) override;
 
   bool IsInteractiveHTMLContent() const override { return true; }
 
@@ -48,16 +46,13 @@ class HTMLDetailsElement final : public nsGenericHTMLElement {
     SetHTMLBoolAttr(nsGkAtoms::open, aOpen, aError);
   }
 
-  void ToggleOpen() {
-    ErrorResult rv;
-    SetOpen(!Open(), rv);
-    rv.SuppressException();
-  }
+  void ToggleOpen() { SetOpen(!Open(), IgnoreErrors()); }
 
   virtual void AsyncEventRunning(AsyncEventDispatcher* aEvent) override;
 
  protected:
   virtual ~HTMLDetailsElement();
+  void SetupShadowTree();
 
   JSObject* WrapNode(JSContext* aCx,
                      JS::Handle<JSObject*> aGivenProto) override;

dom/html/HTMLSummaryElement.cpp

@@ -96,10 +96,14 @@ bool HTMLSummaryElement::IsMainSummary() const {
     return false;
   }
 
-  return details->GetFirstSummary() == this || IsRootOfNativeAnonymousSubtree();
+  return details->GetFirstSummary() == this ||
+         GetContainingShadow() == details->GetShadowRoot();
 }
 
 HTMLDetailsElement* HTMLSummaryElement::GetDetails() const {
+  if (HasBeenInUAWidget()) {
+    return HTMLDetailsElement::FromNodeOrNull(GetContainingShadowHost());
+  }
   return HTMLDetailsElement::FromNodeOrNull(GetParent());
 }
 

dom/html/HTMLSummaryElement.h

@@ -36,7 +36,7 @@ class HTMLSummaryElement final : public nsGenericHTMLElement {
   int32_t TabIndexDefault() override;
 
   // Return true if this is the first summary element child of a details or the
-  // default summary element generated by DetailsFrame.
+  // default summary element.
   bool IsMainSummary() const;
 
   // Return the details element which contains this summary. Otherwise return

layout/base/nsCSSFrameConstructor.cpp

@@ -19,7 +19,6 @@
 #include "mozilla/dom/BindContext.h"
 #include "mozilla/dom/BrowsingContext.h"
 #include "mozilla/dom/GeneratedImageContent.h"
-#include "mozilla/dom/HTMLDetailsElement.h"
 #include "mozilla/dom/HTMLSelectElement.h"
 #include "mozilla/dom/HTMLSharedListElement.h"
 #include "mozilla/dom/HTMLSummaryElement.h"
@@ -110,7 +109,6 @@
 #include "nsIScrollableFrame.h"
 #include "nsBackdropFrame.h"
 #include "nsTransitionManager.h"
-#include "DetailsFrame.h"
 
 #include "nsIPopupContainer.h"
 #ifdef ACCESSIBILITY
@@ -1778,7 +1776,8 @@ void nsCSSFrameConstructor::CreateGeneratedContentItem(
                  aPseudoElement == PseudoStyleType::marker,
              "unexpected aPseudoElement");
 
-  if (HasUAWidget(aOriginatingElement)) {
+  if (HasUAWidget(aOriginatingElement) &&
+      !aOriginatingElement.IsHTMLElement(nsGkAtoms::details)) {
     return;
   }
 
@@ -3209,20 +3208,18 @@ nsIFrame* nsCSSFrameConstructor::ConstructFieldSetFrame(
   return fieldsetFrame;
 }
 
-nsIFrame* nsCSSFrameConstructor::ConstructDetailsFrame(
+nsIFrame* nsCSSFrameConstructor::ConstructDetails(
     nsFrameConstructorState& aState, FrameConstructionItem& aItem,
     nsContainerFrame* aParentFrame, const nsStyleDisplay* aStyleDisplay,
     nsFrameList& aFrameList) {
   if (!aStyleDisplay->IsScrollableOverflow()) {
-    return ConstructNonScrollableBlockWithConstructor(
-        aState, aItem, aParentFrame, aStyleDisplay, aFrameList,
-        NS_NewDetailsFrame);
+    return ConstructNonScrollableBlock(aState, aItem, aParentFrame,
+                                       aStyleDisplay, aFrameList);
   }
 
-  // Build a scroll frame to wrap details frame if necessary.
-  return ConstructScrollableBlockWithConstructor(aState, aItem, aParentFrame,
-                                                 aStyleDisplay, aFrameList,
-                                                 NS_NewDetailsFrame);
+  // Build a scroll frame if necessary.
+  return ConstructScrollableBlock(aState, aItem, aParentFrame, aStyleDisplay,
+                                  aFrameList);
 }
 
 nsIFrame* nsCSSFrameConstructor::ConstructBlockRubyFrame(
@@ -3460,8 +3457,7 @@ nsCSSFrameConstructor::FindHTMLData(const Element& aElement,
       SIMPLE_TAG_CREATE(audio, NS_NewHTMLVideoFrame),
       SIMPLE_TAG_CREATE(progress, NS_NewProgressFrame),
       SIMPLE_TAG_CREATE(meter, NS_NewMeterFrame),
-      COMPLEX_TAG_CREATE(details,
-                         &nsCSSFrameConstructor::ConstructDetailsFrame)};
+      COMPLEX_TAG_CREATE(details, &nsCSSFrameConstructor::ConstructDetails)};
 
   return FindDataByTag(aElement, aStyle, sHTMLData, ArrayLength(sHTMLData));
 }
@@ -4583,15 +4579,6 @@ nsIFrame* nsCSSFrameConstructor::ConstructScrollableBlock(
     nsFrameConstructorState& aState, FrameConstructionItem& aItem,
     nsContainerFrame* aParentFrame, const nsStyleDisplay* aDisplay,
     nsFrameList& aFrameList) {
-  return ConstructScrollableBlockWithConstructor(aState, aItem, aParentFrame,
-                                                 aDisplay, aFrameList,
-                                                 NS_NewBlockFormattingContext);
-}
-
-nsIFrame* nsCSSFrameConstructor::ConstructScrollableBlockWithConstructor(
-    nsFrameConstructorState& aState, FrameConstructionItem& aItem,
-    nsContainerFrame* aParentFrame, const nsStyleDisplay* aDisplay,
-    nsFrameList& aFrameList, BlockFrameCreationFunc aConstructor) {
   nsIContent* const content = aItem.mContent;
   ComputedStyle* const computedStyle = aItem.mComputedStyle;
 
@@ -4603,7 +4590,8 @@ nsIFrame* nsCSSFrameConstructor::ConstructScrollableBlockWithConstructor(
 
   // Create our block frame
   // pass a temporary stylecontext, the correct one will be set later
-  nsContainerFrame* scrolledFrame = aConstructor(mPresShell, computedStyle);
+  nsContainerFrame* scrolledFrame =
+      NS_NewBlockFormattingContext(mPresShell, computedStyle);
 
   // Make sure to AddChild before we call ConstructBlock so that we
   // end up before our descendants in fixed-pos lists as needed.
@@ -4626,14 +4614,6 @@ nsIFrame* nsCSSFrameConstructor::ConstructNonScrollableBlock(
     nsFrameConstructorState& aState, FrameConstructionItem& aItem,
     nsContainerFrame* aParentFrame, const nsStyleDisplay* aDisplay,
     nsFrameList& aFrameList) {
-  return ConstructNonScrollableBlockWithConstructor(
-      aState, aItem, aParentFrame, aDisplay, aFrameList, NS_NewBlockFrame);
-}
-
-nsIFrame* nsCSSFrameConstructor::ConstructNonScrollableBlockWithConstructor(
-    nsFrameConstructorState& aState, FrameConstructionItem& aItem,
-    nsContainerFrame* aParentFrame, const nsStyleDisplay* aDisplay,
-    nsFrameList& aFrameList, BlockFrameCreationFunc aConstructor) {
   ComputedStyle* const computedStyle = aItem.mComputedStyle;
 
   // We want a block formatting context root in paginated contexts for
@@ -4653,7 +4633,7 @@ nsIFrame* nsCSSFrameConstructor::ConstructNonScrollableBlockWithConstructor(
     }
   }
 
-  nsContainerFrame* newFrame = aConstructor(mPresShell, computedStyle);
+  nsContainerFrame* newFrame = NS_NewBlockFrame(mPresShell, computedStyle);
   newFrame->AddStateBits(flags);
   ConstructBlock(
       aState, aItem.mContent,
@@ -5280,35 +5260,6 @@ static bool ShouldSuppressFrameInSelect(const nsIContent* aParent,
   return true;
 }
 
-static bool ShouldSuppressFrameInNonOpenDetails(
-    const HTMLDetailsElement* aDetails, ComputedStyle* aComputedStyle,
-    const nsIContent& aChild) {
-  if (!aDetails || aDetails->Open()) {
-    return false;
-  }
-
-  if (aChild.GetParent() != aDetails) {
-    return true;
-  }
-
-  auto* summary = HTMLSummaryElement::FromNode(aChild);
-  if (summary && summary->IsMainSummary()) {
-    return false;
-  }
-
-  // Don't suppress NAC, unless it's a ::before, inside ::marker, or ::after.
-  if (aChild.IsRootOfNativeAnonymousSubtree() &&
-      !(aChild.IsGeneratedContentContainerForMarker() &&
-        aComputedStyle->StyleList()->mListStylePosition ==
-            NS_STYLE_LIST_STYLE_POSITION_INSIDE) &&
-      !aChild.IsGeneratedContentContainerForBefore() &&
-      !aChild.IsGeneratedContentContainerForAfter()) {
-    return false;
-  }
-
-  return true;
-}
-
 const nsCSSFrameConstructor::FrameConstructionData*
 nsCSSFrameConstructor::FindDataForContent(nsIContent& aContent,
                                           ComputedStyle& aStyle,
@@ -5458,16 +5409,6 @@ void nsCSSFrameConstructor::AddFrameConstructionItemsInternal(
     return;
   }
 
-  // When constructing a child of a non-open <details>, create only the frame
-  // for the main <summary> element, and skip other elements.  This only applies
-  // to things that are not roots of native anonymous subtrees (except for
-  // ::before and ::after); we always want to create "internal" anonymous
-  // content.
-  auto* const details = HTMLDetailsElement::FromNodeOrNull(parent);
-  if (ShouldSuppressFrameInNonOpenDetails(details, aComputedStyle, *aContent)) {
-    return;
-  }
-
   if (aContent->IsHTMLElement(nsGkAtoms::legend) && aParentFrame) {
     const nsFieldSetFrame* const fs = GetFieldSetFrameFor(aParentFrame);
     if (fs && !fs->GetLegend() && !aState.mHasRenderedLegend &&
@@ -5512,16 +5453,6 @@ void nsCSSFrameConstructor::AddFrameConstructionItemsInternal(
     AppendPageBreakItem(aContent, aItems);
   }
 
-  if (details && details->Open()) {
-    const auto* const summary = HTMLSummaryElement::FromNode(aContent);
-    if (summary && summary->IsMainSummary()) {
-      // If details is open, the main summary needs to be rendered as if it is
-      // the first child, so add the item to the front of the item list.
-      item = aItems.PrependItem(this, data, aContent, do_AddRef(aComputedStyle),
-                                aSuppressWhiteSpaceOptimizations);
-    }
-  }
-
   if (!item) {
     item = aItems.AppendItem(this, data, aContent, do_AddRef(aComputedStyle),
                              aSuppressWhiteSpaceOptimizations);
@@ -8141,9 +8072,6 @@ nsIFrame* nsCSSFrameConstructor::CreateContinuingFrame(
   } else if (LayoutFrameType::RubyTextContainer == frameType) {
     newFrame = NS_NewRubyTextContainerFrame(mPresShell, computedStyle);
     newFrame->Init(content, aParentFrame, aFrame);
-  } else if (LayoutFrameType::Details == frameType) {
-    newFrame = NS_NewDetailsFrame(mPresShell, computedStyle);
-    newFrame->Init(content, aParentFrame, aFrame);
   } else {
     MOZ_CRASH("unexpected frame type");
   }
@@ -8390,24 +8318,6 @@ bool nsCSSFrameConstructor::MaybeRecreateContainerForFrameRemoval(
     return true;
   }
 
-  if (parent && parent->IsDetailsFrame()) {
-    HTMLSummaryElement* summary =
-        HTMLSummaryElement::FromNode(aFrame->GetContent());
-    DetailsFrame* detailsFrame = static_cast<DetailsFrame*>(parent);
-
-    // Unlike adding summary element cases, we need to check children of the
-    // parent details frame since at this moment the summary element has been
-    // already removed from the parent details element's child list.
-    if (summary && detailsFrame->HasMainSummaryFrame(aFrame)) {
-      // When removing a summary, we should reframe the parent details frame to
-      // ensure that another summary is used or the default summary is
-      // generated.
-      TRACE("Details / Summary");
-      RecreateFramesForContent(parent->GetContent(), InsertionKind::Async);
-      return true;
-    }
-  }
-
   // Now check for possibly needing to reconstruct due to a pseudo parent
   // For the case of ruby pseudo parent, effectively, only pseudo rb/rt frame
   // need to be checked here, since all other types of parent will be catched
@@ -10588,9 +10498,7 @@ void nsCSSFrameConstructor::ConstructBlock(
   // clang-format on
 
   nsBlockFrame* blockFrame = do_QueryFrame(*aNewFrame);
-  MOZ_ASSERT(blockFrame &&
-                 (blockFrame->IsBlockFrame() || blockFrame->IsDetailsFrame()),
-             "not a block frame nor a details frame?");
+  MOZ_ASSERT(blockFrame && blockFrame->IsBlockFrame(), "not a block frame?");
 
   // Create column hierarchy if necessary.
   const bool needsColumn =
@@ -10691,9 +10599,8 @@ nsBlockFrame* nsCSSFrameConstructor::BeginBuildingColumns(
     nsFrameConstructorState& aState, nsIContent* aContent,
     nsContainerFrame* aParentFrame, nsContainerFrame* aColumnContent,
     ComputedStyle* aComputedStyle) {
-  MOZ_ASSERT(
-      aColumnContent->IsBlockFrame() || aColumnContent->IsDetailsFrame(),
-      "aColumnContent should either be a block frame or a details frame.");
+  MOZ_ASSERT(aColumnContent->IsBlockFrame(),
+             "aColumnContent should be a block frame.");
   MOZ_ASSERT(aComputedStyle->StyleColumn()->IsColumnContainerStyle(),
              "No need to build a column hierarchy!");
 
@@ -11279,17 +11186,6 @@ bool nsCSSFrameConstructor::WipeInsertionParent(nsContainerFrame* aFrame) {
     return true;
   }
 
-  // A <details> that's getting new children. When inserting
-  // elements into <details>, we reframe the <details> and let frame constructor
-  // move the main <summary> to the front when constructing the frame
-  // construction items.
-  if (auto* details =
-          HTMLDetailsElement::FromNodeOrNull(aFrame->GetContent())) {
-    TRACE("Details / Summary");
-    RecreateFramesForContent(details, InsertionKind::Async);
-    return true;
-  }
-
   // Reframe the multi-column container whenever elements insert/append
   // into it because we need to reconstruct column-span split.
   if (aFrame->IsColumnSetWrapperFrame()) {
@@ -11578,9 +11474,6 @@ bool nsCSSFrameConstructor::WipeContainingBlock(
 
   // Situation #5 is a frame in multicol subtree that's getting new children.
   if (aFrame->HasAnyStateBits(NS_FRAME_HAS_MULTI_COLUMN_ANCESTOR)) {
-    MOZ_ASSERT(!aFrame->IsDetailsFrame(),
-               "Inserting elements into <details> should have been reframed!");
-
     bool anyColumnSpanItems = false;
     for (FCItemIterator iter(aItems); !iter.IsDone(); iter.Next()) {
       if (iter.item().mComputedStyle->StyleColumn()->IsColumnSpanStyle()) {

layout/base/nsCSSFrameConstructor.h

@@ -1381,13 +1381,12 @@ class nsCSSFrameConstructor final : public nsFrameManager {
                                    const nsStyleDisplay* aStyleDisplay,
                                    nsFrameList& aFrameList);
 
-  // ConstructDetailsFrame puts the new frame in aFrameList and
-  // handles the kids of the details.
-  nsIFrame* ConstructDetailsFrame(nsFrameConstructorState& aState,
-                                  FrameConstructionItem& aItem,
-                                  nsContainerFrame* aParentFrame,
-                                  const nsStyleDisplay* aStyleDisplay,
-                                  nsFrameList& aFrameList);
+  // <details> always creates a block per spec.
+  nsIFrame* ConstructDetails(nsFrameConstructorState& aState,
+                             FrameConstructionItem& aItem,
+                             nsContainerFrame* aParentFrame,
+                             const nsStyleDisplay* aStyleDisplay,
+                             nsFrameList& aFrameList);
 
   // Creates a block frame wrapping an anonymous ruby frame.
   nsIFrame* ConstructBlockRubyFrame(nsFrameConstructorState& aState,
@@ -1579,15 +1578,6 @@ class nsCSSFrameConstructor final : public nsFrameManager {
                                      const nsStyleDisplay* aDisplay,
                                      nsFrameList& aFrameList);
 
-  /**
-   * Construct a scrollable block frame using the given block frame creation
-   * function.
-   */
-  nsIFrame* ConstructScrollableBlockWithConstructor(
-      nsFrameConstructorState& aState, FrameConstructionItem& aItem,
-      nsContainerFrame* aParentFrame, const nsStyleDisplay* aDisplay,
-      nsFrameList& aFrameList, BlockFrameCreationFunc aConstructor);
-
   /**
    * Construct a non-scrollable block frame
    */
@@ -1597,15 +1587,6 @@ class nsCSSFrameConstructor final : public nsFrameManager {
                                         const nsStyleDisplay* aDisplay,
                                         nsFrameList& aFrameList);
 
-  /**
-   * Construct a non-scrollable block frame using the given block frame creation
-   * function.
-   */
-  nsIFrame* ConstructNonScrollableBlockWithConstructor(
-      nsFrameConstructorState& aState, FrameConstructionItem& aItem,
-      nsContainerFrame* aParentFrame, const nsStyleDisplay* aDisplay,
-      nsFrameList& aFrameList, BlockFrameCreationFunc aConstructor);
-
   /**
    * This adds FrameConstructionItem objects to aItemsToConstruct for the
    * anonymous content returned by an nsIAnonymousContentCreator::

layout/generic/DetailsFrame.cpp

@@ -1,141 +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/. */
-
-#include "DetailsFrame.h"
-
-#include "mozilla/Attributes.h"
-#include "mozilla/PresShell.h"
-#include "mozilla/dom/HTMLDetailsElement.h"
-#include "mozilla/dom/HTMLSummaryElement.h"
-#include "nsContentUtils.h"
-#include "nsPlaceholderFrame.h"
-#include "nsTextNode.h"
-
-using namespace mozilla;
-using namespace mozilla::dom;
-
-NS_IMPL_FRAMEARENA_HELPERS(DetailsFrame)
-
-NS_QUERYFRAME_HEAD(DetailsFrame)
-  NS_QUERYFRAME_ENTRY(DetailsFrame)
-  NS_QUERYFRAME_ENTRY(nsIAnonymousContentCreator)
-NS_QUERYFRAME_TAIL_INHERITING(nsBlockFrame)
-
-nsBlockFrame* NS_NewDetailsFrame(PresShell* aPresShell, ComputedStyle* aStyle) {
-  return new (aPresShell) DetailsFrame(aStyle, aPresShell->GetPresContext());
-}
-
-namespace mozilla {
-
-DetailsFrame::DetailsFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
-    : nsBlockFrame(aStyle, aPresContext, kClassID) {}
-
-DetailsFrame::~DetailsFrame() = default;
-
-void DetailsFrame::SetInitialChildList(ChildListID aListID,
-                                       nsFrameList& aChildList) {
-#ifdef DEBUG
-  if (aListID == kPrincipalList) {
-    CheckValidMainSummary(aChildList);
-  }
-#endif
-
-  nsBlockFrame::SetInitialChildList(aListID, aChildList);
-}
-
-#ifdef DEBUG
-bool DetailsFrame::CheckValidMainSummary(const nsFrameList& aFrameList) const {
-  for (nsIFrame* child : aFrameList) {
-    if (child->IsGeneratedContentFrame()) {
-      continue;
-    }
-    HTMLSummaryElement* summary =
-        HTMLSummaryElement::FromNode(child->GetContent());
-    if (child == aFrameList.FirstChild()) {
-      if (summary && summary->IsMainSummary()) {
-        return true;
-      } else if (child->GetContent() == GetContent()) {
-        // The child frame's content is the same as our content, which means
-        // it's a kind of wrapper frame. Descend into its child list to find
-        // main summary.
-        if (CheckValidMainSummary(child->PrincipalChildList())) {
-          return true;
-        }
-      }
-    } else {
-      NS_ASSERTION(!summary || !summary->IsMainSummary(),
-                   "Rest of the children are either not summary element "
-                   "or are not the main summary!");
-    }
-  }
-  return false;
-}
-#endif
-
-void DetailsFrame::DestroyFrom(nsIFrame* aDestructRoot,
-                               PostDestroyData& aPostDestroyData) {
-  aPostDestroyData.AddAnonymousContent(mDefaultSummary.forget());
-  nsBlockFrame::DestroyFrom(aDestructRoot, aPostDestroyData);
-}
-
-nsresult DetailsFrame::CreateAnonymousContent(
-    nsTArray<ContentInfo>& aElements) {
-  auto* details = HTMLDetailsElement::FromNode(GetContent());
-  if (details->GetFirstSummary()) {
-    return NS_OK;
-  }
-
-  // The <details> element lacks any direct <summary> child. Create a default
-  // <summary> element as an anonymous content.
-  nsNodeInfoManager* nodeInfoManager =
-      GetContent()->NodeInfo()->NodeInfoManager();
-
-  RefPtr<NodeInfo> nodeInfo = nodeInfoManager->GetNodeInfo(
-      nsGkAtoms::summary, nullptr, kNameSpaceID_XHTML, nsINode::ELEMENT_NODE);
-  mDefaultSummary = new (nodeInfoManager) HTMLSummaryElement(nodeInfo.forget());
-
-  nsAutoString defaultSummaryText;
-  nsContentUtils::GetMaybeLocalizedString(
-      nsContentUtils::eFORMS_PROPERTIES, "DefaultSummary",
-      GetContent()->OwnerDoc(), defaultSummaryText);
-  RefPtr<nsTextNode> description =
-      new (nodeInfoManager) nsTextNode(nodeInfoManager);
-  description->SetText(defaultSummaryText, false);
-  mDefaultSummary->AppendChildTo(description, false, IgnoreErrors());
-
-  aElements.AppendElement(mDefaultSummary);
-
-  return NS_OK;
-}
-
-void DetailsFrame::AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
-                                            uint32_t aFilter) {
-  if (mDefaultSummary) {
-    aElements.AppendElement(mDefaultSummary);
-  }
-}
-
-bool DetailsFrame::HasMainSummaryFrame(nsIFrame* aSummaryFrame) {
-  const ChildListIDs flowLists = {kPrincipalList, kOverflowList};
-  for (nsIFrame* frag = this; frag; frag = frag->GetNextInFlow()) {
-    for (const auto& [list, listID] : frag->ChildLists()) {
-      if (!flowLists.contains(listID)) {
-        continue;
-      }
-      for (nsIFrame* child : list) {
-        child = nsPlaceholderFrame::GetRealFrameFor(child);
-        // We skip any non-primary frames such as a list-style-position:inside
-        // bullet frame for the <details> itself.
-        if (!child->IsGeneratedContentFrame()) {
-          return aSummaryFrame == child;
-        }
-      }
-    }
-  }
-  return false;
-}
-
-}  // namespace mozilla

layout/generic/DetailsFrame.h

@@ -1,67 +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 DetailsFrame_h
-#define DetailsFrame_h
-
-#include "nsBlockFrame.h"
-#include "nsIAnonymousContentCreator.h"
-
-class nsContainerFrame;
-
-namespace mozilla {
-
-// DetailsFrame is generated by HTMLDetailsElement. See
-// nsCSSFrameConstructor::ConstructDetailsFrame for the structure of a
-// DetailsFrame.
-//
-class DetailsFrame final : public nsBlockFrame,
-                           public nsIAnonymousContentCreator {
- public:
-  NS_DECL_FRAMEARENA_HELPERS(DetailsFrame)
-  NS_DECL_QUERYFRAME
-
-  explicit DetailsFrame(ComputedStyle* aStyle, nsPresContext* aPresContext);
-
-  virtual ~DetailsFrame();
-
-#ifdef DEBUG_FRAME_DUMP
-  nsresult GetFrameName(nsAString& aResult) const override {
-    return MakeFrameName(u"Details"_ns, aResult);
-  }
-#endif
-
-#ifdef DEBUG
-  // Check the frame of the main summary element is the first child in the frame
-  // list. Returns true if we found the main summary frame; false otherwise.
-  bool CheckValidMainSummary(const nsFrameList& aFrameList) const;
-#endif
-
-  void SetInitialChildList(ChildListID aListID,
-                           nsFrameList& aChildList) override;
-
-  void DestroyFrom(nsIFrame* aDestructRoot,
-                   PostDestroyData& aPostDestroyData) override;
-
-  // nsIAnonymousContentCreator
-  nsresult CreateAnonymousContent(nsTArray<ContentInfo>& aElements) override;
-
-  void AppendAnonymousContentTo(nsTArray<nsIContent*>& aElements,
-                                uint32_t aFilter) override;
-  // Returns true if |aSummaryFrame| is the main summary (i.e. the first child
-  // of this details frame).
-  // This function is used when the summary element is removed from the parent
-  // details element since at that moment the summary element has been already
-  // removed from the details element children.
-  bool HasMainSummaryFrame(nsIFrame* aSummaryFrame);
-
- private:
-  nsCOMPtr<nsIContent> mDefaultSummary;
-};
-
-}  // namespace mozilla
-
-#endif  // DetailsFrame_h

layout/generic/FrameClasses.py

@@ -7,7 +7,6 @@ from FrameClass import Frame, AbstractFrame, LEAF, NOT_LEAF, DYNAMIC_LEAF
 
 FRAME_CLASSES = [
     Frame("BRFrame", "Br", LEAF),
-    Frame("DetailsFrame", "Details", NOT_LEAF),
     Frame("nsBCTableCellFrame", "TableCell", NOT_LEAF),
     Frame("nsBackdropFrame", "Backdrop", LEAF),
     Frame("nsBlockFrame", "Block", NOT_LEAF),

layout/generic/moz.build

@@ -165,7 +165,6 @@ UNIFIED_SOURCES += [
     "ColumnUtils.cpp",
     "CSSAlignUtils.cpp",
     "CSSOrderAwareFrameIterator.cpp",
-    "DetailsFrame.cpp",
     "FrameChildList.cpp",
     "MathMLTextRunFactory.cpp",
     "nsAbsoluteContainingBlock.cpp",

layout/generic/nsHTMLParts.h

@@ -157,8 +157,6 @@ nsIFrame* NS_NewDateTimeControlFrame(mozilla::PresShell* aPresShell,
                                      mozilla::ComputedStyle* aStyle);
 nsIFrame* NS_NewSearchControlFrame(mozilla::PresShell* aPresShell,
                                    mozilla::ComputedStyle* aStyle);
-nsBlockFrame* NS_NewDetailsFrame(mozilla::PresShell* aPresShell,
-                                 mozilla::ComputedStyle* aStyle);
 
 // Table frame factories
 class nsTableWrapperFrame;

layout/reftests/details-summary/details-after-ref.html

@@ -0,0 +1,5 @@
+<!doctype html>
+<div id="details">
+  <div id="summary">Summary</div>
+  <p>This is the details.</p>
+</div>

layout/reftests/details-summary/details-after.html

@@ -3,6 +3,9 @@
    - http://creativecommons.org/publicdomain/zero/1.0/ -->
 <head>
   <style>
+    summary {
+      list-style-type: none;
+    }
     details::after {
       content: "This is the details.";
       /* Match the margins and display of <p> */

layout/reftests/details-summary/details-before-ref.html

@@ -0,0 +1,5 @@
+<!doctype html>
+<div id="details">
+  <p>This is the details.</p>
+  <div id="summary">Summary</div>
+</div>

layout/reftests/details-summary/details-before.html

@@ -3,6 +3,9 @@
    - http://creativecommons.org/publicdomain/zero/1.0/ -->
 <head>
   <style>
+    summary {
+      list-style-type: none;
+    }
     details::before {
       content: "This is the details.";
       /* Match the margins and display of <p> */

layout/reftests/details-summary/details-first-line-ref.html

@@ -3,11 +3,6 @@
    - http://creativecommons.org/publicdomain/zero/1.0/ -->
 
 <html>
-  <style>
-  div#details::first-line {
-    color: blue;
-  }
-  </style>
   <body>
     <div id="details">
       <span>Summary

layout/reftests/details-summary/details-in-ol-ref.html

@@ -7,7 +7,7 @@
     <ol>
       <li>First item
         <div>
-          <summary>Summary
+          <summary style="list-style-position: inside">Summary
             <ul>
               <li>First unordered item in summary</li>
               <li>Second unordered item in summary</li>

layout/reftests/details-summary/open-details-before.html

@@ -3,6 +3,9 @@
    - http://creativecommons.org/publicdomain/zero/1.0/ -->
 <head>
   <style>
+    summary {
+      list-style-type: none;
+    }
     details::before {
       content: "This is the details.";
       /* Match the margins and display of <p> */

layout/reftests/details-summary/open-details-first-line-ref.html

@@ -3,11 +3,6 @@
    - http://creativecommons.org/publicdomain/zero/1.0/ -->
 
 <html>
-  <style>
-  div#details::first-line {
-    color: blue;
-  }
-  </style>
   <body>
     <div id="details">
       <span>Summary

layout/reftests/details-summary/reftest.list

@@ -85,10 +85,10 @@ fuzzy-if(geckoview,0-7,0-1) == mouse-click-float-details.html open-float-details
 fuzzy(0-4,0-1) == mouse-click-twice-float-details.html float-details.html # Bug 1316430
 
 # Generated content bits
-== details-after.html single-summary.html
-== details-before.html single-summary.html
+== details-after.html details-after-ref.html
+== details-before.html details-before-ref.html
 == open-details-after.html open-single-summary.html
-== open-details-before.html open-single-summary.html
+== open-details-before.html details-before-ref.html
 
 # Move summary element
 == move-float-summary-to-different-details.html move-float-summary-to-different-details-ref.html

layout/style/Loader.cpp

@@ -108,6 +108,10 @@ mozilla::LazyLogModule sCssLoaderLog("nsCSSLoader");
 
 static mozilla::LazyLogModule gSriPRLog("SRI");
 
+static bool IsPrivilegedURI(nsIURI* aURI) {
+  return aURI->SchemeIs("chrome") || aURI->SchemeIs("resource");
+}
+
 #define LOG_ERROR(args) MOZ_LOG(sCssLoaderLog, mozilla::LogLevel::Error, args)
 #define LOG_WARN(args) MOZ_LOG(sCssLoaderLog, mozilla::LogLevel::Warning, args)
 #define LOG_DEBUG(args) MOZ_LOG(sCssLoaderLog, mozilla::LogLevel::Debug, args)
@@ -169,7 +173,7 @@ bool SheetLoadDataHashKey::KeyEquals(const SheetLoadDataHashKey& aKey) const {
   }
 
   // Chrome URIs ignore everything else.
-  if (dom::IsChromeURI(mURI)) {
+  if (IsPrivilegedURI(mURI)) {
     return true;
   }
 
@@ -1821,8 +1825,8 @@ Result<Loader::LoadSheetResult, nsresult> Loader::LoadStyleLink(
 
   nsINode* requestingNode =
       aInfo.mContent ? static_cast<nsINode*>(aInfo.mContent) : mDocument;
-  bool syncLoad = aInfo.mContent && aInfo.mContent->IsInUAWidget() &&
-                  IsChromeURI(aInfo.mURI);
+  const bool syncLoad = aInfo.mContent && aInfo.mContent->IsInUAWidget() &&
+                        IsPrivilegedURI(aInfo.mURI);
   LOG(("  Link sync load: '%s'", syncLoad ? "true" : "false"));
   MOZ_ASSERT_IF(syncLoad, !aObserver);
 

layout/style/moz.build

@@ -271,6 +271,7 @@ RESOURCE_FILES += [
 
 CONTENT_ACCESSIBLE_FILES += [
     "ImageDocument.css",
+    "res/details.css",
     "res/plaintext.css",
     "res/searchfield-cancel.svg",
     "res/viewsource.css",

layout/style/res/details.css

@@ -0,0 +1,22 @@
+/* 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/. */
+
+slot:not([name]) {
+  display: none;
+}
+/* Either the fallback summary (inside the shadow tree), or the slotted main
+   summary. */
+summary,
+slot[name=internal-main-summary]::slotted(summary) {
+  display: list-item;
+  counter-increment: list-item 0;
+  list-style: disclosure-closed inside;
+}
+:host([open]) summary,
+:host([open]) slot[name=internal-main-summary]::slotted(summary) {
+  list-style-type: disclosure-open;
+}
+:host([open]) slot:not([name]) {
+  display: revert;
+}

layout/style/res/html.css

@@ -782,27 +782,6 @@ video > .caption-box {
             display direction, maybe related with bug 1558431. */
 }
 
-/* details & summary */
-details > summary:-moz-native-anonymous {
-  /* TODO(krosylight): Remove this when fixing bug 1308080 */
-  user-select: none;
-}
-
-details > summary:is(:first-of-type, :-moz-native-anonymous) {
-  display: list-item;
-  counter-increment: list-item 0;
-  list-style: disclosure-closed inside;
-}
-
-details[open] > summary:is(:first-of-type, :-moz-native-anonymous) {
-  list-style-type: disclosure-open;
-}
-
-details > summary:first-of-type > *|* {
-  /* Cancel "list-style-position: inside" inherited from summary. */
-  list-style-position: initial;
-}
-
 /* <dialog> element styles */
 
 dialog {

testing/web-platform/meta/css/css-multicol/multicol-span-all-dynamic-add-013.html.ini

@@ -0,0 +1,7 @@
+[multicol-span-all-dynamic-add-013.html]
+  bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1791144
+  expected:
+    if os == "win": FAIL
+    if os == "mac": FAIL
+    PASS
+

testing/web-platform/meta/html/rendering/the-details-element/details-after.html.ini

@@ -1,2 +0,0 @@
-[details-after.html]
-  expected: FAIL

testing/web-platform/meta/html/rendering/the-details-element/details-before.html.ini

@@ -1,2 +0,0 @@
-[details-before.html]
-  expected: FAIL