--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@@ -236,21 +236,16 @@ DOMInterfaces = {
     'wrapperCache': False
 },
 
 'CSSMozDocumentRule': {
     'nativeType': 'mozilla::css::DocumentRule',
     'headerFile': 'nsCSSRules.h',
 },
 
-'CSSPageRule': {
-    'nativeType': 'nsCSSPageRule',
-    'headerFile': 'nsCSSRules.h',
-},
-
 'CSSPrimitiveValue': {
     'nativeType': 'nsROCSSPrimitiveValue',
 },
 
 'CSSRule': {
     'concrete': False,
     'nativeType': 'mozilla::css::Rule'
 },

new file mode 100644
--- /dev/null
+++ b/layout/style/CSSPageRule.cpp
@@ -0,0 +1,36 @@
+/* -*- 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 "mozilla/dom/CSSPageRule.h"
+
+#include "mozilla/dom/CSSPageRuleBinding.h"
+
+namespace mozilla {
+namespace dom {
+
+NS_IMPL_ADDREF_INHERITED(CSSPageRule, css::Rule)
+NS_IMPL_RELEASE_INHERITED(CSSPageRule, css::Rule)
+
+// QueryInterface implementation for CSSPageRule
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(CSSPageRule)
+  NS_INTERFACE_MAP_ENTRY(nsIDOMCSSPageRule)
+NS_INTERFACE_MAP_END_INHERITING(css::Rule)
+
+NS_IMETHODIMP
+CSSPageRule::GetStyle(nsIDOMCSSStyleDeclaration** aStyle)
+{
+  NS_ADDREF(*aStyle = Style());
+  return NS_OK;
+}
+
+JSObject*
+CSSPageRule::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
+{
+  return CSSPageRuleBinding::Wrap(aCx, this, aGivenProto);
+}
+
+} // namespace dom
+} // namespace mozilla

new file mode 100644
--- /dev/null
+++ b/layout/style/CSSPageRule.h
@@ -0,0 +1,52 @@
+/* -*- 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 mozilla_dom_CSSPageRule_h
+#define mozilla_dom_CSSPageRule_h
+
+#include "mozilla/css/Rule.h"
+
+#include "nsICSSDeclaration.h"
+#include "nsIDOMCSSPageRule.h"
+#include "nsIDOMCSSStyleDeclaration.h"
+
+namespace mozilla {
+namespace dom {
+
+class CSSPageRule : public css::Rule
+                  , public nsIDOMCSSPageRule
+{
+protected:
+  using Rule::Rule;
+  virtual ~CSSPageRule() {};
+
+public:
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // nsIDOMCSSPageRule interface
+  NS_DECL_NSIDOMCSSPAGERULE
+
+  virtual bool IsCCLeaf() const override = 0;
+
+  int32_t GetType() const final { return Rule::PAGE_RULE; }
+  using Rule::GetType;
+
+  // WebIDL interfaces
+  uint16_t Type() const final { return nsIDOMCSSRule::PAGE_RULE; }
+  virtual void GetCssTextImpl(nsAString& aCssText) const override = 0;
+  virtual nsICSSDeclaration* Style() = 0;
+
+  virtual size_t
+  SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const override = 0;
+
+  JSObject*
+  WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_CSSPageRule_h

--- a/layout/style/moz.build
+++ b/layout/style/moz.build
@@ -126,16 +126,17 @@ EXPORTS.mozilla += [
     'URLExtraData.h',
 ]
 
 EXPORTS.mozilla.dom += [
     'CSS.h',
     'CSSLexer.h',
     'CSSMediaRule.h',
     'CSSNamespaceRule.h',
+    'CSSPageRule.h',
     'CSSRuleList.h',
     'CSSValue.h',
     'FontFace.h',
     'FontFaceSet.h',
     'FontFaceSetIterator.h',
     'MediaList.h',
     'MediaQueryList.h',
 ]
@@ -155,16 +156,17 @@ EXPORTS.mozilla.css += [
 
 UNIFIED_SOURCES += [
     'AnimationCollection.cpp',
     'BindingStyleRule.cpp',
     'CounterStyleManager.cpp',
     'CSS.cpp',
     'CSSLexer.cpp',
     'CSSMediaRule.cpp',
+    'CSSPageRule.cpp',
     'CSSRuleList.cpp',
     'CSSStyleSheet.cpp',
     'CSSVariableDeclarations.cpp',
     'CSSVariableResolver.cpp',
     'CSSVariableValues.cpp',
     'Declaration.cpp',
     'DocumentStyleRootIterator.cpp',
     'ErrorReporter.cpp',

--- a/layout/style/nsCSSRules.cpp
+++ b/layout/style/nsCSSRules.cpp
@@ -33,17 +33,16 @@
 #include "nsStyleUtil.h"
 #include "mozilla/DeclarationBlockInlines.h"
 #include "nsCSSParser.h"
 #include "nsDOMClassInfoID.h"
 #include "mozilla/dom/CSSStyleDeclarationBinding.h"
 #include "mozilla/dom/CSSImportRuleBinding.h"
 #include "mozilla/dom/CSSSupportsRuleBinding.h"
 #include "mozilla/dom/CSSMozDocumentRuleBinding.h"
-#include "mozilla/dom/CSSPageRuleBinding.h"
 #include "mozilla/dom/CSSFontFaceRuleBinding.h"
 #include "mozilla/dom/CSSFontFeatureValuesRuleBinding.h"
 #include "mozilla/dom/CSSKeyframeRuleBinding.h"
 #include "mozilla/dom/CSSKeyframesRuleBinding.h"
 #include "mozilla/dom/CSSCounterStyleRuleBinding.h"
 #include "StyleRule.h"
 #include "nsFont.h"
 #include "nsIURI.h"
@@ -2156,17 +2155,17 @@ nsCSSPageStyleDeclaration::GetParentObje
 }
 
 // -------------------------------------------
 // nsCSSPageRule
 //
 
 nsCSSPageRule::nsCSSPageRule(const nsCSSPageRule& aCopy)
   // copy everything except our reference count and mDOMDeclaration
-  : Rule(aCopy)
+  : dom::CSSPageRule(aCopy)
   , mDeclaration(new css::Declaration(*aCopy.mDeclaration))
 {
   mDeclaration->SetOwningRule(this);
 }
 
 nsCSSPageRule::~nsCSSPageRule()
 {
   mDeclaration->SetOwningRule(nullptr);
@@ -2177,44 +2176,43 @@ nsCSSPageRule::~nsCSSPageRule()
 
 /* virtual */ already_AddRefed<css::Rule>
 nsCSSPageRule::Clone() const
 {
   RefPtr<css::Rule> clone = new nsCSSPageRule(*this);
   return clone.forget();
 }
 
-NS_IMPL_ADDREF_INHERITED(nsCSSPageRule, mozilla::css::Rule)
-NS_IMPL_RELEASE_INHERITED(nsCSSPageRule, mozilla::css::Rule)
+NS_IMPL_ADDREF_INHERITED(nsCSSPageRule, dom::CSSPageRule)
+NS_IMPL_RELEASE_INHERITED(nsCSSPageRule, dom::CSSPageRule)
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(nsCSSPageRule)
 
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(nsCSSPageRule,
-                                                mozilla::css::Rule)
+                                                dom::CSSPageRule)
   if (tmp->mDOMDeclaration) {
     tmp->mDOMDeclaration->DropReference();
     tmp->mDOMDeclaration = nullptr;
   }
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(nsCSSPageRule,
-                                                  mozilla::css::Rule)
+                                                  dom::CSSPageRule)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDOMDeclaration)
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
 bool
 nsCSSPageRule::IsCCLeaf() const
 {
   // Let's not worry about figuring out whether we're a leaf or not.
   return false;
 }
 
 // QueryInterface implementation for nsCSSPageRule
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(nsCSSPageRule)
-  NS_INTERFACE_MAP_ENTRY(nsIDOMCSSPageRule)
-NS_INTERFACE_MAP_END_INHERITING(mozilla::css::Rule)
+NS_INTERFACE_MAP_END_INHERITING(dom::CSSPageRule)
 
 #ifdef DEBUG
 void
 nsCSSPageRule::List(FILE* out, int32_t aIndent) const
 {
   nsAutoCString str;
   for (int32_t indent = aIndent; --indent >= 0; ) {
     str.AppendLiteral("  ");
@@ -2224,45 +2222,26 @@ nsCSSPageRule::List(FILE* out, int32_t a
   nsAutoString tmp;
   mDeclaration->ToString(tmp);
   AppendUTF16toUTF8(tmp, str);
   str.AppendLiteral("}\n");
   fprintf_stderr(out, "%s", str.get());
 }
 #endif
 
-/* virtual */ int32_t
-nsCSSPageRule::GetType() const
-{
-  return Rule::PAGE_RULE;
-}
-
-uint16_t
-nsCSSPageRule::Type() const
-{
-  return nsIDOMCSSRule::PAGE_RULE;
-}
-
 void
 nsCSSPageRule::GetCssTextImpl(nsAString& aCssText) const
 {
   aCssText.AppendLiteral("@page { ");
   nsAutoString tmp;
   mDeclaration->ToString(tmp);
   aCssText.Append(tmp);
   aCssText.AppendLiteral(" }");
 }
 
-NS_IMETHODIMP
-nsCSSPageRule::GetStyle(nsIDOMCSSStyleDeclaration** aStyle)
-{
-  NS_ADDREF(*aStyle = Style());
-  return NS_OK;
-}
-
 nsICSSDeclaration*
 nsCSSPageRule::Style()
 {
   if (!mDOMDeclaration) {
     mDOMDeclaration = new nsCSSPageStyleDeclaration(this);
   }
   return mDOMDeclaration;
 }
@@ -2282,23 +2261,16 @@ nsCSSPageRule::ChangeDeclaration(css::De
 }
 
 /* virtual */ size_t
 nsCSSPageRule::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
 {
   return aMallocSizeOf(this);
 }
 
-/* virtual */ JSObject*
-nsCSSPageRule::WrapObject(JSContext* aCx,
-                          JS::Handle<JSObject*> aGivenProto)
-{
-  return CSSPageRuleBinding::Wrap(aCx, this, aGivenProto);
-}
-
 namespace mozilla {
 
 CSSSupportsRule::CSSSupportsRule(bool aConditionMet,
                                  const nsString& aCondition,
                                  uint32_t aLineNumber, uint32_t aColumnNumber)
   : css::ConditionRule(aLineNumber, aColumnNumber)
   , mUseGroup(aConditionMet)
   , mCondition(aCondition)

--- a/layout/style/nsCSSRules.h
+++ b/layout/style/nsCSSRules.h
@@ -13,26 +13,26 @@
 #include "StyleRule.h"
 #include "gfxFontFeatures.h"
 #include "mozilla/Attributes.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Move.h"
 #include "mozilla/SheetType.h"
 #include "mozilla/css/GroupRule.h"
 #include "mozilla/dom/CSSMediaRule.h"
+#include "mozilla/dom/CSSPageRule.h"
 #include "nsAutoPtr.h"
 #include "nsCSSPropertyID.h"
 #include "nsCSSValue.h"
 #include "nsDOMCSSDeclaration.h"
 #include "nsIDOMCSSConditionRule.h"
 #include "nsIDOMCSSCounterStyleRule.h"
 #include "nsIDOMCSSFontFeatureValuesRule.h"
 #include "nsIDOMCSSGroupingRule.h"
 #include "nsIDOMCSSMozDocumentRule.h"
-#include "nsIDOMCSSPageRule.h"
 #include "nsIDOMCSSSupportsRule.h"
 #include "nsIDOMCSSKeyframeRule.h"
 #include "nsIDOMCSSKeyframesRule.h"
 #include "nsTArray.h"
 
 class nsMediaList;
 
 namespace mozilla {
@@ -400,59 +400,49 @@ public:
 protected:
   virtual ~nsCSSPageStyleDeclaration();
 
   // This reference is not reference-counted. The rule object tells us
   // when it's about to go away.
   nsCSSPageRule* MOZ_NON_OWNING_REF mRule;
 };
 
-class nsCSSPageRule final : public mozilla::css::Rule,
-                            public nsIDOMCSSPageRule
+class nsCSSPageRule final : public mozilla::dom::CSSPageRule
 {
 public:
   nsCSSPageRule(mozilla::css::Declaration* aDeclaration,
                 uint32_t aLineNumber, uint32_t aColumnNumber)
-    : mozilla::css::Rule(aLineNumber, aColumnNumber)
+    : mozilla::dom::CSSPageRule(aLineNumber, aColumnNumber)
     , mDeclaration(aDeclaration)
   {
     mDeclaration->SetOwningRule(this);
   }
 private:
   nsCSSPageRule(const nsCSSPageRule& aCopy);
   ~nsCSSPageRule();
 public:
   NS_DECL_ISUPPORTS_INHERITED
-  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(nsCSSPageRule, mozilla::css::Rule)
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(nsCSSPageRule, mozilla::dom::CSSPageRule)
   virtual bool IsCCLeaf() const override;
 
 #ifdef DEBUG
   virtual void List(FILE* out = stdout, int32_t aIndent = 0) const override;
 #endif
-  virtual int32_t GetType() const override;
-  using Rule::GetType;
   virtual already_AddRefed<mozilla::css::Rule> Clone() const override;
 
-  // nsIDOMCSSPageRule interface
-  NS_DECL_NSIDOMCSSPAGERULE
-
-  // WebIDL interface
-  uint16_t Type() const override;
-  void GetCssTextImpl(nsAString& aCssText) const override;
-  nsICSSDeclaration* Style();
+  // WebIDL interfaces
+  virtual void GetCssTextImpl(nsAString& aCssText) const override;
+  virtual nsICSSDeclaration* Style() override;
 
   mozilla::css::Declaration* Declaration()   { return mDeclaration; }
 
   void ChangeDeclaration(mozilla::css::Declaration* aDeclaration);
 
   virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const override;
 
-  virtual JSObject* WrapObject(JSContext* aCx,
-                               JS::Handle<JSObject*> aGivenProto) override;
-
 private:
   RefPtr<mozilla::css::Declaration>     mDeclaration;
   // lazily created when needed:
   RefPtr<nsCSSPageStyleDeclaration>     mDOMDeclaration;
 };
 
 namespace mozilla {