diff --git a/dom/base/nsDOMClassInfo.cpp b/dom/base/nsDOMClassInfo.cpp
index d74cc63d93..f1c0ca43ec 100644
--- a/dom/base/nsDOMClassInfo.cpp
+++ b/dom/base/nsDOMClassInfo.cpp
@@ -72,8 +72,6 @@
 #include "nsMemory.h"
 
 // includes needed for the prototype chain interfaces
-#include "nsIDOMCSSKeyframeRule.h"
-#include "nsIDOMCSSKeyframesRule.h"
 #include "nsIDOMCSSCounterStyleRule.h"
 #include "nsIDOMXULCommandDispatcher.h"
 #include "nsIControllers.h"
@@ -219,10 +217,6 @@ static nsDOMClassInfoData sClassInfoData[] = {
                                        DOM_DEFAULT_SCRIPTABLE_FLAGS)
 
 
-  NS_DEFINE_CLASSINFO_DATA(CSSKeyframesRule, nsDOMGenericSH,
-                           DOM_DEFAULT_SCRIPTABLE_FLAGS |
-                           nsIXPCScriptable::WANT_PRECREATE)
-
   NS_DEFINE_CLASSINFO_DATA(CSSCounterStyleRule, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS |
                            nsIXPCScriptable::WANT_PRECREATE)
@@ -543,11 +537,6 @@ nsDOMClassInfo::Init()
     DOM_CLASSINFO_MAP_ENTRY(nsIMessageSender)
   DOM_CLASSINFO_MAP_END
 
-  DOM_CLASSINFO_MAP_BEGIN(CSSKeyframesRule, nsIDOMCSSKeyframesRule)
-    DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSRule)
-    DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSKeyframesRule)
-  DOM_CLASSINFO_MAP_END
-
   DOM_CLASSINFO_MAP_BEGIN(CSSCounterStyleRule, nsIDOMCSSCounterStyleRule)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSRule)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSCounterStyleRule)
diff --git a/dom/base/nsDOMClassInfoClasses.h b/dom/base/nsDOMClassInfoClasses.h
index d6423723b6..ad96206cdb 100644
--- a/dom/base/nsDOMClassInfoClasses.h
+++ b/dom/base/nsDOMClassInfoClasses.h
@@ -27,8 +27,6 @@ DOMCI_CLASS(ContentProcessMessageManager)
 DOMCI_CLASS(ChromeMessageBroadcaster)
 DOMCI_CLASS(ChromeMessageSender)
 
-DOMCI_CLASS(CSSKeyframesRule)
-
 // @counter-style in CSS
 DOMCI_CLASS(CSSCounterStyleRule)
 
diff --git a/dom/base/nsWrapperCache.h b/dom/base/nsWrapperCache.h
index 65fddff476..3adaaa25e8 100644
--- a/dom/base/nsWrapperCache.h
+++ b/dom/base/nsWrapperCache.h
@@ -23,7 +23,6 @@ class ProcessGlobal;
 class SandboxPrivate;
 class nsInProcessTabChildGlobal;
 class nsWindowRoot;
-class nsCSSKeyframesRule;
 class nsCSSCounterStyleRule;
 
 #define NS_WRAPPERCACHE_IID \
@@ -282,7 +281,6 @@ private:
   friend class SandboxPrivate;
   friend class nsInProcessTabChildGlobal;
   friend class nsWindowRoot;
-  friend class nsCSSKeyframesRule;
   friend class nsCSSCounterStyleRule;
 
   void SetIsNotDOMBinding()
diff --git a/dom/bindings/Bindings.conf b/dom/bindings/Bindings.conf
index 4a527ca97a..fcc2727220 100644
--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@@ -227,6 +227,11 @@ DOMInterfaces = {
     'headerFile': 'nsCSSRules.h',
 },
 
+'CSSKeyframesRule': {
+    'nativeType': 'nsCSSKeyframesRule',
+    'headerFile': 'nsCSSRules.h',
+},
+
 'CSSLexer': {
     'wrapperCache': False
 },
diff --git a/dom/webidl/CSSKeyframesRule.webidl b/dom/webidl/CSSKeyframesRule.webidl
new file mode 100644
index 0000000000..d0ea978d03
--- /dev/null
+++ b/dom/webidl/CSSKeyframesRule.webidl
@@ -0,0 +1,18 @@
+/* -*- 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/css-animations/#interface-csskeyframesrule
+ */
+
+// https://drafts.csswg.org/css-animations/#interface-csskeyframesrule
+interface CSSKeyframesRule : CSSRule {
+           attribute DOMString   name;
+  readonly attribute CSSRuleList cssRules;
+
+  void            appendRule(DOMString rule);
+  void            deleteRule(DOMString select);
+  CSSKeyframeRule? findRule(DOMString select);
+};
diff --git a/dom/webidl/moz.build b/dom/webidl/moz.build
index 0b0c421135..18d4fdc2b5 100644
--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -96,6 +96,7 @@ WEBIDL_FILES = [
     'CSSGroupingRule.webidl',
     'CSSImportRule.webidl',
     'CSSKeyframeRule.webidl',
+    'CSSKeyframesRule.webidl',
     'CSSLexer.webidl',
     'CSSMediaRule.webidl',
     'CSSMozDocumentRule.webidl',
diff --git a/layout/style/nsCSSRules.cpp b/layout/style/nsCSSRules.cpp
index ecec902de5..5c99fbd37c 100644
--- a/layout/style/nsCSSRules.cpp
+++ b/layout/style/nsCSSRules.cpp
@@ -42,6 +42,7 @@
 #include "mozilla/dom/CSSFontFaceRuleBinding.h"
 #include "mozilla/dom/CSSFontFeatureValuesRuleBinding.h"
 #include "mozilla/dom/CSSKeyframeRuleBinding.h"
+#include "mozilla/dom/CSSKeyframesRuleBinding.h"
 #include "StyleRule.h"
 #include "nsFont.h"
 #include "nsIURI.h"
@@ -2316,7 +2317,6 @@ nsCSSKeyframesRule::nsCSSKeyframesRule(const nsCSSKeyframesRule& aCopy)
   : GroupRule(aCopy),
     mName(aCopy.mName)
 {
-  SetIsNotDOMBinding();
 }
 
 nsCSSKeyframesRule::~nsCSSKeyframesRule()
@@ -2336,7 +2336,6 @@ NS_IMPL_RELEASE_INHERITED(nsCSSKeyframesRule, css::GroupRule)
 // QueryInterface implementation for nsCSSKeyframesRule
 NS_INTERFACE_MAP_BEGIN(nsCSSKeyframesRule)
   NS_INTERFACE_MAP_ENTRY(nsIDOMCSSKeyframesRule)
-  NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(CSSKeyframesRule)
 NS_INTERFACE_MAP_END_INHERITING(GroupRule)
 
 #ifdef DEBUG
@@ -2501,14 +2500,19 @@ nsCSSKeyframesRule::DeleteRule(const nsAString& aKey)
 NS_IMETHODIMP
 nsCSSKeyframesRule::FindRule(const nsAString& aKey,
                              nsIDOMCSSKeyframeRule** aResult)
+{
+  NS_IF_ADDREF(*aResult = FindRule(aKey));
+  return NS_OK;
+}
+
+nsCSSKeyframeRule*
+nsCSSKeyframesRule::FindRule(const nsAString& aKey)
 {
   uint32_t index = FindRuleIndexForKey(aKey);
   if (index == RULE_NOT_FOUND) {
-    *aResult = nullptr;
-  } else {
-    NS_ADDREF(*aResult = static_cast<nsCSSKeyframeRule*>(mRules[index]));
+    return nullptr;
   }
-  return NS_OK;
+  return static_cast<nsCSSKeyframeRule*>(mRules[index]);
 }
 
 // GroupRule interface
@@ -2537,8 +2541,7 @@ nsCSSKeyframesRule::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
 nsCSSKeyframesRule::WrapObject(JSContext* aCx,
                                JS::Handle<JSObject*> aGivenProto)
 {
-  NS_NOTREACHED("We called SetIsNotDOMBinding() in our constructor");
-  return nullptr;
+  return CSSKeyframesRuleBinding::Wrap(aCx, this, aGivenProto);
 }
 
 // -------------------------------------------
diff --git a/layout/style/nsCSSRules.h b/layout/style/nsCSSRules.h
index ceb20e5a1d..81e4f04cfb 100644
--- a/layout/style/nsCSSRules.h
+++ b/layout/style/nsCSSRules.h
@@ -470,7 +470,6 @@ public:
     : mozilla::css::GroupRule(aLineNumber, aColumnNumber)
     , mName(aName)
   {
-    SetIsNotDOMBinding();
   }
 private:
   nsCSSKeyframesRule(const nsCSSKeyframesRule& aCopy);
@@ -492,6 +491,12 @@ public:
   // WebIDL interface
   uint16_t Type() const override;
   void GetCssTextImpl(nsAString& aCssText) const override;
+  // The XPCOM GetName is OK
+  // The XPCOM SetName is OK
+  using mozilla::css::GroupRule::CssRules;
+  // The XPCOM appendRule is OK, since it never throws
+  // The XPCOM deleteRule is OK, since it never throws
+  nsCSSKeyframeRule* FindRule(const nsAString& aKey);
 
   // rest of GroupRule
   virtual bool UseForPresentation(nsPresContext* aPresContext,