--- a/dom/base/Document.cpp
+++ b/dom/base/Document.cpp
@@ -86,16 +86,17 @@
 #include "mozilla/dom/BindingDeclarations.h"
 #include "mozilla/dom/ContentChild.h"
 #include "mozilla/dom/CSPDictionariesBinding.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/Event.h"
 #include "mozilla/dom/FeaturePolicy.h"
 #include "mozilla/dom/FeaturePolicyUtils.h"
 #include "mozilla/dom/FramingChecker.h"
+#include "mozilla/dom/HTMLAllCollection.h"
 #include "mozilla/dom/HTMLSharedElement.h"
 #include "mozilla/dom/Navigator.h"
 #include "mozilla/dom/Performance.h"
 #include "mozilla/dom/TreeOrderedArrayInlines.h"
 #include "mozilla/dom/ResizeObserver.h"
 #include "mozilla/dom/ResizeObserverController.h"
 #include "mozilla/dom/ServiceWorkerContainer.h"
 #include "mozilla/dom/ScriptLoader.h"
@@ -1998,16 +1999,17 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mApplets);
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAnchors);
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAnonymousContents)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCommandDispatcher)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mFeaturePolicy)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSuppressedEventListener)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPrototypeDocument)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mMidasCommandManager)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAll)
 
   // Traverse all our nsCOMArrays.
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mPreloadingImages)
 
   for (uint32_t i = 0; i < tmp->mFrameRequestCallbacks.Length(); ++i) {
     NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mFrameRequestCallbacks[i]");
     cb.NoteXPCOMChild(tmp->mFrameRequestCallbacks[i].mCallback);
   }
@@ -5626,16 +5628,23 @@ void Document::SetFgColor(const nsAStrin
     body->SetText(aFgColor);
   }
 }
 
 void Document::CaptureEvents() { WarnOnceAbout(Document::eUseOfCaptureEvents); }
 
 void Document::ReleaseEvents() { WarnOnceAbout(Document::eUseOfReleaseEvents); }
 
+HTMLAllCollection* Document::All() {
+  if (!mAll) {
+    mAll = new HTMLAllCollection(this);
+  }
+  return mAll;
+}
+
 nsresult Document::GetSrcdocData(nsAString& aSrcdocData) {
   if (mIsSrcdocDocument) {
     nsCOMPtr<nsIInputStreamChannel> inStrmChan = do_QueryInterface(mChannel);
     if (inStrmChan) {
       return inStrmChan->GetSrcdocData(aSrcdocData);
     }
   }
   aSrcdocData = VoidString();

--- a/dom/base/Document.h
+++ b/dom/base/Document.h
@@ -180,16 +180,17 @@ class DOMStringList;
 class Element;
 struct ElementCreationOptions;
 class Event;
 class EventTarget;
 class FeaturePolicy;
 class FontFaceSet;
 class FrameRequestCallback;
 class ImageTracker;
+class HTMLAllCollection;
 class HTMLBodyElement;
 class HTMLSharedElement;
 class HTMLImageElement;
 struct LifecycleCallbackArgs;
 class Link;
 class Location;
 class MediaQueryList;
 class GlobalObject;
@@ -3574,16 +3575,18 @@ class Document : public nsINode,
   void GetBgColor(nsAString& aBgColor);
   void SetBgColor(const nsAString& aBgColor);
   void Clear() const {
     // Deprecated
   }
   void CaptureEvents();
   void ReleaseEvents();
 
+  mozilla::dom::HTMLAllCollection* All();
+
   static bool IsUnprefixedFullscreenEnabled(JSContext* aCx, JSObject* aObject);
   static bool DocumentSupportsL10n(JSContext* aCx, JSObject* aObject);
   static bool IsWebAnimationsEnabled(JSContext* aCx, JSObject* aObject);
   static bool IsWebAnimationsEnabled(CallerType aCallerType);
   static bool IsWebAnimationsGetAnimationsEnabled(JSContext* aCx,
                                                   JSObject* aObject);
   static bool AreWebAnimationsImplicitKeyframesEnabled(JSContext* aCx,
                                                        JSObject* aObject);
@@ -5203,16 +5206,18 @@ class Document : public nsINode,
   uint32_t mIgnoreOpensDuringUnloadCounter;
 
   nsCOMPtr<nsIDOMXULCommandDispatcher>
       mCommandDispatcher;  // [OWNER] of the focus tracker
 
   RefPtr<XULBroadcastManager> mXULBroadcastManager;
   RefPtr<XULPersist> mXULPersist;
 
+  RefPtr<mozilla::dom::HTMLAllCollection> mAll;
+
   // document lightweight theme for use with :-moz-lwtheme,
   // :-moz-lwtheme-brighttext and :-moz-lwtheme-darktext
   DocumentTheme mDocLWTheme;
 
   // Pres shell resolution saved before entering fullscreen mode.
   float mSavedResolution;
 
   bool mPendingInitialTranslation;

--- a/dom/html/HTMLAllCollection.cpp
+++ b/dom/html/HTMLAllCollection.cpp
@@ -3,23 +3,25 @@
 /* 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 "mozilla/dom/HTMLAllCollection.h"
 
 #include "mozilla/dom/HTMLAllCollectionBinding.h"
 #include "mozilla/dom/Nullable.h"
+#include "mozilla/dom/Document.h"
 #include "mozilla/dom/Element.h"
-#include "nsHTMLDocument.h"
+#include "nsContentList.h"
+#include "nsGenericHTMLElement.h"
 
 namespace mozilla {
 namespace dom {
 
-HTMLAllCollection::HTMLAllCollection(nsHTMLDocument* aDocument)
+HTMLAllCollection::HTMLAllCollection(mozilla::dom::Document* aDocument)
     : mDocument(aDocument) {
   MOZ_ASSERT(mDocument);
 }
 
 HTMLAllCollection::~HTMLAllCollection() {}
 
 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(HTMLAllCollection, mDocument, mCollection,
                                       mNamedMap)

--- a/dom/html/HTMLAllCollection.h
+++ b/dom/html/HTMLAllCollection.h
@@ -10,34 +10,34 @@
 #include "nsCycleCollectionParticipant.h"
 #include "nsISupportsImpl.h"
 #include "nsRefPtrHashtable.h"
 #include "nsWrapperCache.h"
 
 #include <stdint.h>
 
 class nsContentList;
-class nsHTMLDocument;
 class nsINode;
 
 namespace mozilla {
 namespace dom {
 
+class Document;
 class Element;
 class OwningHTMLCollectionOrElement;
 template <typename>
 struct Nullable;
 template <typename>
 class Optional;
 
 class HTMLAllCollection final : public nsISupports, public nsWrapperCache {
   ~HTMLAllCollection();
 
  public:
-  explicit HTMLAllCollection(nsHTMLDocument* aDocument);
+  explicit HTMLAllCollection(mozilla::dom::Document* aDocument);
 
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(HTMLAllCollection)
 
   virtual JSObject* WrapObject(JSContext* aCx,
                                JS::Handle<JSObject*> aGivenProto) override;
   nsINode* GetParentObject() const;
 
@@ -75,17 +75,17 @@ class HTMLAllCollection final : public n
    */
   nsContentList* GetDocumentAllList(const nsAString& aID);
 
   /**
    * Helper for indexed getter and spec Item() method.
    */
   Element* Item(uint32_t aIndex);
 
-  RefPtr<nsHTMLDocument> mDocument;
+  RefPtr<mozilla::dom::Document> mDocument;
   RefPtr<nsContentList> mCollection;
   nsRefPtrHashtable<nsStringHashKey, nsContentList> mNamedMap;
 };
 
 }  // namespace dom
 }  // namespace mozilla
 
 #endif  // mozilla_dom_HTMLAllCollection_h

--- a/dom/html/nsHTMLDocument.cpp
+++ b/dom/html/nsHTMLDocument.cpp
@@ -4,17 +4,16 @@
  * 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 "nsHTMLDocument.h"
 
 #include "nsIContentPolicy.h"
 #include "mozilla/DebugOnly.h"
 #include "mozilla/PresShell.h"
-#include "mozilla/dom/HTMLAllCollection.h"
 #include "nsCommandManager.h"
 #include "nsCOMPtr.h"
 #include "nsGlobalWindow.h"
 #include "nsString.h"
 #include "nsPrintfCString.h"
 #include "nsReadableUtils.h"
 #include "nsUnicharUtils.h"
 #include "nsIContentSecurityPolicy.h"
@@ -153,20 +152,16 @@ nsHTMLDocument::nsHTMLDocument()
       mIsPlainText(false) {
   mType = eHTML;
   mDefaultElementType = kNameSpaceID_XHTML;
   mCompatMode = eCompatibility_NavQuirks;
 }
 
 nsHTMLDocument::~nsHTMLDocument() {}
 
-NS_IMPL_CYCLE_COLLECTION_INHERITED(nsHTMLDocument, Document, mAll)
-
-NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED_0(nsHTMLDocument, Document)
-
 JSObject* nsHTMLDocument::WrapNode(JSContext* aCx,
                                    JS::Handle<JSObject*> aGivenProto) {
   return HTMLDocument_Binding::Wrap(aCx, this, aGivenProto);
 }
 
 nsresult nsHTMLDocument::Init() {
   nsresult rv = Document::Init();
   NS_ENSURE_SUCCESS(rv, rv);
@@ -775,23 +770,16 @@ void nsHTMLDocument::GetSupportedNames(n
 
 // forms related stuff
 
 bool nsHTMLDocument::MatchFormControls(Element* aElement, int32_t aNamespaceID,
                                        nsAtom* aAtom, void* aData) {
   return aElement->IsNodeOfType(nsIContent::eHTML_FORM_CONTROL);
 }
 
-HTMLAllCollection* nsHTMLDocument::All() {
-  if (!mAll) {
-    mAll = new HTMLAllCollection(this);
-  }
-  return mAll;
-}
-
 nsresult nsHTMLDocument::Clone(dom::NodeInfo* aNodeInfo,
                                nsINode** aResult) const {
   NS_ASSERTION(aNodeInfo->NodeInfoManager() == mNodeInfoManager,
                "Can't import this document into another document!");
 
   RefPtr<nsHTMLDocument> clone = new nsHTMLDocument();
   nsresult rv = CloneDocHelper(clone.get());
   NS_ENSURE_SUCCESS(rv, rv);

--- a/dom/html/nsHTMLDocument.h
+++ b/dom/html/nsHTMLDocument.h
@@ -22,17 +22,16 @@
 class nsCommandManager;
 class nsIURI;
 class nsIDocShell;
 class nsICachingChannel;
 class nsILoadGroup;
 
 namespace mozilla {
 namespace dom {
-class HTMLAllCollection;
 template <typename T>
 struct Nullable;
 class WindowProxyHolder;
 }  // namespace dom
 }  // namespace mozilla
 
 class nsHTMLDocument : public mozilla::dom::Document {
  protected:
@@ -44,19 +43,16 @@ class nsHTMLDocument : public mozilla::d
 
  public:
   using Document::GetPlugins;
   using Document::SetDocumentURI;
 
   nsHTMLDocument();
   virtual nsresult Init() override;
 
-  NS_DECL_ISUPPORTS_INHERITED
-  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(nsHTMLDocument, Document)
-
   // Document
   virtual void Reset(nsIChannel* aChannel, nsILoadGroup* aLoadGroup) override;
   virtual void ResetToURI(nsIURI* aURI, nsILoadGroup* aLoadGroup,
                           nsIPrincipal* aPrincipal,
                           nsIPrincipal* aStoragePrincipal) override;
 
   virtual nsresult StartDocumentLoad(const char* aCommand, nsIChannel* aChannel,
                                      nsILoadGroup* aLoadGroup,
@@ -68,18 +64,16 @@ class nsHTMLDocument : public mozilla::d
  protected:
   virtual bool UseWidthDeviceWidthFallbackViewport() const override;
 
  public:
   virtual Element* GetUnfocusedKeyEventTarget() override;
 
   nsContentList* GetExistingForms() const { return mForms; }
 
-  mozilla::dom::HTMLAllCollection* All();
-
   // Returns whether an object was found for aName.
   bool ResolveName(JSContext* aCx, const nsAString& aName,
                    JS::MutableHandle<JS::Value> aRetval,
                    mozilla::ErrorResult& aError);
 
   /**
    * Called when form->BindToTree() is called so that document knows
    * immediately when a form is added
@@ -167,18 +161,16 @@ class nsHTMLDocument : public mozilla::d
     RefPtr<nsHTMLDocument> mDocument;
     RefPtr<nsContentList> mFormList;
     RefPtr<nsContentList> mFormControlList;
   };
 
   friend class ContentListHolder;
   ContentListHolder* mContentListHolder;
 
-  RefPtr<mozilla::dom::HTMLAllCollection> mAll;
-
   /** # of forms in the document, synchronously set */
   int32_t mNumForms;
 
   static void TryHintCharset(nsIContentViewer* aContentViewer,
                              int32_t& aCharsetSource,
                              NotNull<const Encoding*>& aEncoding);
   void TryUserForcedCharset(nsIContentViewer* aCv, nsIDocShell* aDocShell,
                             int32_t& aCharsetSource,

--- a/dom/webidl/Document.webidl
+++ b/dom/webidl/Document.webidl
@@ -271,17 +271,17 @@ partial interface Document {
 
   void clear();
   // @deprecated These are old Netscape 4 methods. Do not use,
   //             the implementation is no-op.
   // XXXbz do we actually need these anymore?
   void captureEvents();
   void releaseEvents();
 
-  //(HTML only)[SameObject] readonly attribute HTMLAllCollection all;
+  [SameObject] readonly attribute HTMLAllCollection all;
 };
 
 // https://fullscreen.spec.whatwg.org/#api
 partial interface Document {
   // Note: Per spec the 'S' in these two is lowercase, but the "Moz"
   // versions have it uppercase.
   [LenientSetter, Unscopable, Func="Document::IsUnprefixedFullscreenEnabled"]
   readonly attribute boolean fullscreen;

--- a/dom/webidl/HTMLDocument.webidl
+++ b/dom/webidl/HTMLDocument.webidl
@@ -4,18 +4,16 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
 [OverrideBuiltins]
 interface HTMLDocument : Document {
   // DOM tree accessors
   [Throws]
   getter object (DOMString name);
-
-  readonly attribute HTMLAllCollection all;
 };
 
 partial interface HTMLDocument {
   /*
    * Number of nodes that have been blocked by the Safebrowsing API to prevent
    * tracking, cryptomining and so on. This method is for testing only.
    */
   [ChromeOnly, Pure]

--- a/testing/web-platform/meta/html/dom/interfaces.https.html.ini
+++ b/testing/web-platform/meta/html/dom/interfaces.https.html.ini
@@ -1,13 +1,10 @@
 prefs: [dom.security.featurePolicy.enabled:true]
 [interfaces.https.html?include=(Document|Window)]
-  [Document interface: attribute all]
-    expected: FAIL
-
   [Document interface: attribute oncancel]
     expected: FAIL
 
   [Document interface: attribute onsecuritypolicyviolation]
     expected: FAIL
 
   [Document interface: iframe.contentDocument must inherit property "defaultView" with the proper type]
     expected: FAIL
@@ -25,19 +22,16 @@ prefs: [dom.security.featurePolicy.enabl
     expected: FAIL
 
   [Document interface: new Document() must inherit property "oncancel" with the proper type]
     expected: FAIL
 
   [Document interface: new Document() must inherit property "onsecuritypolicyviolation" with the proper type]
     expected: FAIL
 
-  [Document interface: document.implementation.createDocument(null, "", null) must inherit property "all" with the proper type]
-    expected: FAIL
-
   [Document interface: document.implementation.createDocument(null, "", null) must inherit property "oncancel" with the proper type]
     expected: FAIL
 
   [Document interface: document.implementation.createDocument(null, "", null) must inherit property "onsecuritypolicyviolation" with the proper type]
     expected: FAIL
 
   [Window interface: attribute oncancel]
     expected: FAIL