diff --git a/dom/base/nsDOMClassInfo.cpp b/dom/base/nsDOMClassInfo.cpp
index 6af55170b22d..c6ce77fa91c6 100644
--- a/dom/base/nsDOMClassInfo.cpp
+++ b/dom/base/nsDOMClassInfo.cpp
@@ -199,6 +199,9 @@ static nsDOMClassInfoData sClassInfoData[] = {
   NS_DEFINE_CLASSINFO_DATA(CSSMediaRule, nsCSSRuleSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS |
                            nsIXPCScriptable::WANT_PRECREATE)
+  NS_DEFINE_CLASSINFO_DATA(CSSNameSpaceRule, nsCSSRuleSH,
+                           DOM_DEFAULT_SCRIPTABLE_FLAGS |
+                           nsIXPCScriptable::WANT_PRECREATE)
 
   // XUL classes
 #ifdef MOZ_XUL
@@ -536,6 +539,10 @@ nsDOMClassInfo::Init()
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSMediaRule)
   DOM_CLASSINFO_MAP_END
 
+  DOM_CLASSINFO_MAP_BEGIN_NO_CLASS_IF(CSSNameSpaceRule, nsIDOMCSSRule)
+    DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSRule)
+  DOM_CLASSINFO_MAP_END
+
 #ifdef MOZ_XUL
   DOM_CLASSINFO_MAP_BEGIN(XULCommandDispatcher, nsIDOMXULCommandDispatcher)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMXULCommandDispatcher)
diff --git a/dom/base/nsDOMClassInfoID.h b/dom/base/nsDOMClassInfoID.h
index 88b7876e03e7..8a71ae209086 100644
--- a/dom/base/nsDOMClassInfoID.h
+++ b/dom/base/nsDOMClassInfoID.h
@@ -23,6 +23,7 @@ enum nsDOMClassInfoID
   eDOMClassInfo_CSSStyleRule_id,
   eDOMClassInfo_CSSImportRule_id,
   eDOMClassInfo_CSSMediaRule_id,
+  eDOMClassInfo_CSSNameSpaceRule_id,
 
   // XUL classes
 #ifdef MOZ_XUL
diff --git a/dom/base/nsWrapperCache.h b/dom/base/nsWrapperCache.h
index 343c0689e1d4..13f298d72d1d 100644
--- a/dom/base/nsWrapperCache.h
+++ b/dom/base/nsWrapperCache.h
@@ -21,6 +21,7 @@ class ProcessGlobal;
 } // namespace dom
 namespace css {
 class ImportRule;
+class NameSpaceRule;
 class StyleRule;
 class MediaRule;
 class DocumentRule;
@@ -295,6 +296,7 @@ private:
   friend class nsInProcessTabChildGlobal;
   friend class nsWindowRoot;
   friend class mozilla::css::ImportRule;
+  friend class mozilla::css::NameSpaceRule;
   friend class mozilla::css::StyleRule;
   friend class mozilla::css::MediaRule;
   friend class mozilla::css::DocumentRule;
diff --git a/dom/bindings/Bindings.conf b/dom/bindings/Bindings.conf
index 92376c14d5be..7f5f27ee2b6c 100644
--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@@ -200,17 +200,12 @@ DOMInterfaces = {
     'wrapperCache': False
 },
 
-'CSSNamespaceRule': {
-    'nativeType': 'mozilla::css::NameSpaceRule',
-},
-
 'CSSPrimitiveValue': {
     'nativeType': 'nsROCSSPrimitiveValue',
 },
 
 'CSSRule': {
     'hasXPConnectImpls': True,
-    'concrete': False,
     'nativeType': 'mozilla::css::Rule'
 },
 
diff --git a/dom/media/webaudio/AudioBuffer.h b/dom/media/webaudio/AudioBuffer.h
index 4d6f468e58d6..35627d7a1cbf 100644
--- a/dom/media/webaudio/AudioBuffer.h
+++ b/dom/media/webaudio/AudioBuffer.h
@@ -15,7 +15,6 @@
 #include "nsTArray.h"
 #include "js/TypeDecls.h"
 #include "mozilla/MemoryReporting.h"
-#include "mozilla/dom/TypedArray.h"
 
 namespace mozilla {
 
diff --git a/dom/tests/mochitest/general/test_interfaces.html b/dom/tests/mochitest/general/test_interfaces.html
index 5c15aa716bc4..618a4a219f74 100644
--- a/dom/tests/mochitest/general/test_interfaces.html
+++ b/dom/tests/mochitest/general/test_interfaces.html
@@ -249,7 +249,7 @@ var interfaceNamesInGlobalScope =
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "CSSMozDocumentRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
-    "CSSNamespaceRule",
+    "CSSNameSpaceRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "CSSPageRule",
 // IMPORTANT: Do not change this list without review from a DOM peer!
diff --git a/dom/webidl/CSSNamespaceRule.webidl b/dom/webidl/CSSNamespaceRule.webidl
deleted file mode 100644
index 0051c904a72d..000000000000
--- a/dom/webidl/CSSNamespaceRule.webidl
+++ /dev/null
@@ -1,16 +0,0 @@
-/* -*- Mode: IDL; 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/.
- *
- * The origin of this IDL file is
- * https://drafts.csswg.org/cssom/#cssnamespacerule
- */
-
-// https://drafts.csswg.org/cssom/#cssnamespacerule
-interface CSSNamespaceRule : CSSRule {
-  // Not implemented yet.  <See
-  // https://bugzilla.mozilla.org/show_bug.cgi?id=1326514>.
-  //  readonly attribute DOMString namespaceURI;
-  //  readonly attribute DOMString prefix;
-};
diff --git a/dom/webidl/moz.build b/dom/webidl/moz.build
index 1462eb863574..11d8c8d24125 100644
--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -90,7 +90,6 @@ WEBIDL_FILES = [
     'CSS.webidl',
     'CSSAnimation.webidl',
     'CSSLexer.webidl',
-    'CSSNamespaceRule.webidl',
     'CSSPrimitiveValue.webidl',
     'CSSPseudoElement.webidl',
     'CSSRule.webidl',
diff --git a/layout/style/nsCSSRules.cpp b/layout/style/nsCSSRules.cpp
index 0a5d0b7e2e99..48d644415108 100644
--- a/layout/style/nsCSSRules.cpp
+++ b/layout/style/nsCSSRules.cpp
@@ -33,7 +33,6 @@
 #include "nsCSSParser.h"
 #include "nsDOMClassInfoID.h"
 #include "mozilla/dom/CSSStyleDeclarationBinding.h"
-#include "mozilla/dom/CSSNamespaceRuleBinding.h"
 #include "StyleRule.h"
 #include "nsFont.h"
 #include "nsIURI.h"
@@ -1121,6 +1120,7 @@ NameSpaceRule::NameSpaceRule(nsIAtom* aPrefix, const nsString& aURLSpec,
     mPrefix(aPrefix),
     mURLSpec(aURLSpec)
 {
+  SetIsNotDOMBinding();
 }
 
 NameSpaceRule::NameSpaceRule(const NameSpaceRule& aCopy)
@@ -1128,6 +1128,7 @@ NameSpaceRule::NameSpaceRule(const NameSpaceRule& aCopy)
     mPrefix(aCopy.mPrefix),
     mURLSpec(aCopy.mURLSpec)
 {
+  SetIsNotDOMBinding();
 }
 
 NameSpaceRule::~NameSpaceRule()
@@ -1147,6 +1148,7 @@ NS_INTERFACE_MAP_BEGIN(NameSpaceRule)
     return NS_OK;
   }
   else
+  NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(CSSNameSpaceRule)
 NS_INTERFACE_MAP_END_INHERITING(Rule)
 
 bool
@@ -1227,7 +1229,8 @@ NameSpaceRule::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
 NameSpaceRule::WrapObject(JSContext* aCx,
                           JS::Handle<JSObject*> aGivenProto)
 {
-  return CSSNamespaceRuleBinding::Wrap(aCx, this, aGivenProto);
+  NS_NOTREACHED("We called SetIsNotDOMBinding() in our constructor");
+  return nullptr;
 }
 
 } // namespace css