diff --git a/dom/base/nsDOMClassInfo.cpp b/dom/base/nsDOMClassInfo.cpp
index 3b5a5a1f17..18115dbba2 100644
--- a/dom/base/nsDOMClassInfo.cpp
+++ b/dom/base/nsDOMClassInfo.cpp
@@ -80,7 +80,6 @@
 #include "nsIDOMCSSSupportsRule.h"
 #include "nsIDOMCSSCounterStyleRule.h"
 #include "nsIDOMCSSPageRule.h"
-#include "nsIDOMCSSStyleRule.h"
 #include "nsIDOMXULCommandDispatcher.h"
 #include "nsIControllers.h"
 #ifdef MOZ_XUL
@@ -188,9 +187,6 @@ static nsDOMClassInfoData sClassInfoData[] = {
   // Misc Core related classes
 
   // CSS classes
-  NS_DEFINE_CLASSINFO_DATA(CSSStyleRule, nsCSSRuleSH,
-                           DOM_DEFAULT_SCRIPTABLE_FLAGS |
-                           nsIXPCScriptable::WANT_PRECREATE)
   NS_DEFINE_CLASSINFO_DATA(CSSMediaRule, nsCSSRuleSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS |
                            nsIXPCScriptable::WANT_PRECREATE)
@@ -516,11 +512,6 @@ nsDOMClassInfo::Init()
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMDOMConstructor)
   DOM_CLASSINFO_MAP_END
 
-  DOM_CLASSINFO_MAP_BEGIN(CSSStyleRule, nsIDOMCSSStyleRule)
-    DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSRule)
-    DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSStyleRule)
-  DOM_CLASSINFO_MAP_END
-
   DOM_CLASSINFO_MAP_BEGIN(CSSMediaRule, nsIDOMCSSMediaRule)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSRule)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMCSSMediaRule)
@@ -2000,14 +1991,6 @@ nsCSSRuleSH::PreCreate(nsISupports *nativeObj, JSContext *cx,
     return NS_ERROR_UNEXPECTED;
   }
   css::Rule* cssRule = rule->GetCSSRule();
-  if (!cssRule) {
-    // A DOMCSSStyleRule whose actual underlying rule has gone away.  There
-    // isn't much a caller can do with this thing anyway, and only chrome code
-    // can get its hands on it to start with, so just wrap in the current
-    // global.
-    *parentObj = globalObj;
-    return NS_OK;
-  }
   nsIDocument* doc = cssRule->GetDocument();
   if (!doc) {
     *parentObj = globalObj;
diff --git a/dom/base/nsDOMClassInfoClasses.h b/dom/base/nsDOMClassInfoClasses.h
index 90dbb32a72..ff3e57f60c 100644
--- a/dom/base/nsDOMClassInfoClasses.h
+++ b/dom/base/nsDOMClassInfoClasses.h
@@ -8,7 +8,6 @@ DOMCI_CLASS(DOMPrototype)
 DOMCI_CLASS(DOMConstructor)
 
 // CSS classes
-DOMCI_CLASS(CSSStyleRule)
 DOMCI_CLASS(CSSMediaRule)
 
 // XUL classes
diff --git a/dom/base/nsWrapperCache.h b/dom/base/nsWrapperCache.h
index eb366e8baa..df83a8f234 100644
--- a/dom/base/nsWrapperCache.h
+++ b/dom/base/nsWrapperCache.h
@@ -19,7 +19,6 @@ class TabChildGlobal;
 class ProcessGlobal;
 } // namespace dom
 namespace css {
-class StyleRule;
 class MediaRule;
 class DocumentRule;
 } // namespace css
@@ -291,7 +290,6 @@ private:
   friend class SandboxPrivate;
   friend class nsInProcessTabChildGlobal;
   friend class nsWindowRoot;
-  friend class mozilla::css::StyleRule;
   friend class mozilla::css::MediaRule;
   friend class mozilla::css::DocumentRule;
   friend class mozilla::CSSSupportsRule;
diff --git a/dom/bindings/Bindings.conf b/dom/bindings/Bindings.conf
index 08387439c7..5c91365834 100644
--- a/dom/bindings/Bindings.conf
+++ b/dom/bindings/Bindings.conf
@@ -223,6 +223,10 @@ DOMInterfaces = {
     'nativeType': 'nsICSSDeclaration'
 },
 
+'CSSStyleRule': {
+    'nativeType': 'mozilla::BindingStyleRule',
+},
+
 'CSSStyleSheet': {
     'nativeType': 'mozilla::StyleSheet',
     'binaryNames': { 'ownerRule': 'DOMOwnerRule' },
diff --git a/dom/webidl/CSSStyleRule.webidl b/dom/webidl/CSSStyleRule.webidl
new file mode 100644
index 0000000000..571bd6a57f
--- /dev/null
+++ b/dom/webidl/CSSStyleRule.webidl
@@ -0,0 +1,14 @@
+/* -*- 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/#the-cssstylerule-interface
+ */
+
+// https://drafts.csswg.org/cssom/#the-cssstylerule-interface
+interface CSSStyleRule : CSSRule {
+  attribute DOMString selectorText;
+  [SameObject, PutForwards=cssText] readonly attribute CSSStyleDeclaration style;
+};
diff --git a/dom/webidl/LegacyQueryInterface.webidl b/dom/webidl/LegacyQueryInterface.webidl
index 96048b03ca..41bbd025ff 100644
--- a/dom/webidl/LegacyQueryInterface.webidl
+++ b/dom/webidl/LegacyQueryInterface.webidl
@@ -26,6 +26,7 @@ Comment implements LegacyQueryInterface;
 Crypto implements LegacyQueryInterface;
 CSSPrimitiveValue implements LegacyQueryInterface;
 CSSStyleDeclaration implements LegacyQueryInterface;
+CSSStyleRule implements LegacyQueryInterface;
 CSSValueList implements LegacyQueryInterface;
 DOMImplementation implements LegacyQueryInterface;
 DOMParser implements LegacyQueryInterface;
diff --git a/dom/webidl/moz.build b/dom/webidl/moz.build
index 820af99089..3f20beac79 100644
--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -98,6 +98,7 @@ WEBIDL_FILES = [
     'CSSRule.webidl',
     'CSSRuleList.webidl',
     'CSSStyleDeclaration.webidl',
+    'CSSStyleRule.webidl',
     'CSSStyleSheet.webidl',
     'CSSTransition.webidl',
     'CSSValue.webidl',
diff --git a/js/xpconnect/tests/mochitest/file_crosscompartment_weakmap.html b/js/xpconnect/tests/mochitest/file_crosscompartment_weakmap.html
index b25cdb2f90..127c479ebe 100644
--- a/js/xpconnect/tests/mochitest/file_crosscompartment_weakmap.html
+++ b/js/xpconnect/tests/mochitest/file_crosscompartment_weakmap.html
@@ -1,7 +1,6 @@
 <!DOCTYPE HTML>
 <html>
 <head>
-  <link rel="stylesheet" href="data:text/css,div {}">
   <title>Test Cross-Compartment DOM WeakMaps</title>
 </head>
 <body>
diff --git a/js/xpconnect/tests/mochitest/test_crosscompartment_weakmap.html b/js/xpconnect/tests/mochitest/test_crosscompartment_weakmap.html
index e50b1f1bd8..54658d17bc 100644
--- a/js/xpconnect/tests/mochitest/test_crosscompartment_weakmap.html
+++ b/js/xpconnect/tests/mochitest/test_crosscompartment_weakmap.html
@@ -15,14 +15,6 @@ function setup() {
   var item = window.frames[0].document.querySelector("body");
 
   my_map.set(item, "success_string");
-
-  var rule_fail = false;
-  try {
-    my_map.set(window.frames[0].document.styleSheets[0].cssRules[0], 1);
-  } catch (e) {
-    rule_fail = true;
-  }
-  ok(rule_fail, "Using rule as a weak map key across compartments should produce an exception because it can't be wrapper preserved.");
 }
 
 function runTest() {
diff --git a/layout/style/BindingStyleRule.cpp b/layout/style/BindingStyleRule.cpp
new file mode 100644
index 0000000000..9cdbc46cdd
--- /dev/null
+++ b/layout/style/BindingStyleRule.cpp
@@ -0,0 +1,18 @@
+/* -*- Mode: C++; 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/. */
+
+#include "mozilla/BindingStyleRule.h"
+#include "mozilla/dom/CSSStyleRuleBinding.h"
+
+namespace mozilla {
+
+/* virtual */ JSObject*
+BindingStyleRule::WrapObject(JSContext* aCx,
+			     JS::Handle<JSObject*> aGivenProto)
+{
+  return dom::CSSStyleRuleBinding::Wrap(aCx, this, aGivenProto);
+}
+
+} // namespace mozilla
diff --git a/layout/style/BindingStyleRule.h b/layout/style/BindingStyleRule.h
new file mode 100644
index 0000000000..e371bc1149
--- /dev/null
+++ b/layout/style/BindingStyleRule.h
@@ -0,0 +1,60 @@
+/* -*- Mode: C++; 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/. */
+
+#ifndef mozilla_BindingStyleRule_h__
+#define mozilla_BindingStyleRule_h__
+
+#include "nscore.h"
+#include "nsStringGlue.h"
+#include "mozilla/css/Rule.h"
+
+/**
+ * Superclass for mozilla::css::StyleRule, for use from bindings code.
+ */
+
+class nsICSSDeclaration;
+
+namespace mozilla {
+
+class BindingStyleRule : public css::Rule
+{
+protected:
+  BindingStyleRule(uint32_t aLineNumber, uint32_t aColumnNumber)
+    : css::Rule(aLineNumber, aColumnNumber)
+  {
+  }
+  BindingStyleRule(const BindingStyleRule& aCopy)
+    : css::Rule(aCopy)
+  {
+  }
+  virtual ~BindingStyleRule() {}
+
+public:
+  // This is pure virtual because we have no members, and are an abstract class
+  // to start with.  The fact that we have to have this declaration at all is
+  // kinda dumb.  :(
+  virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf)
+    const override MOZ_MUST_OVERRIDE = 0;
+
+  // Likewise for this one.  We have to override our superclass, but don't
+  // really need to do anything in this method.
+  virtual bool IsCCLeaf() const override MOZ_MUST_OVERRIDE = 0;
+
+  // WebIDL API
+  // For GetSelectorText/SetSelectorText, we purposefully use a signature that
+  // matches the nsIDOMCSSStyleRule one for now, so subclasses can just
+  // implement both at once.  The actual implementations must never return
+  // anything other than NS_OK;
+  NS_IMETHOD GetSelectorText(nsAString& aSelectorText) = 0;
+  NS_IMETHOD SetSelectorText(const nsAString& aSelectorText) = 0;
+  virtual nsICSSDeclaration* Style() = 0;
+
+  virtual JSObject* WrapObject(JSContext* aCx,
+                               JS::Handle<JSObject*> aGivenProto) override;
+};
+
+} // namespace mozilla
+
+#endif // mozilla_BindingStyleRule_h__
diff --git a/layout/style/StyleRule.cpp b/layout/style/StyleRule.cpp
index cf5952a650..97a17d2871 100644
--- a/layout/style/StyleRule.cpp
+++ b/layout/style/StyleRule.cpp
@@ -15,6 +15,7 @@
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/css/GroupRule.h"
 #include "mozilla/css/Declaration.h"
+#include "mozilla/dom/CSSStyleRuleBinding.h"
 #include "nsIDocument.h"
 #include "nsIAtom.h"
 #include "nsString.h"
@@ -26,7 +27,6 @@
 #include "nsCSSPseudoClasses.h"
 #include "nsCSSAnonBoxes.h"
 #include "nsTArray.h"
-#include "nsDOMClassInfoID.h"
 #include "nsContentUtils.h"
 #include "nsError.h"
 #include "mozAutoDocUpdate.h"
@@ -1235,13 +1235,18 @@ StyleRule::Type() const
 
 NS_IMETHODIMP
 StyleRule::GetStyle(nsIDOMCSSStyleDeclaration** aStyle)
+{
+  NS_ADDREF(*aStyle = Style());
+  return NS_OK;
+}
+
+nsICSSDeclaration*
+StyleRule::Style()
 {
   if (!mDOMDeclaration) {
     mDOMDeclaration.reset(new DOMCSSDeclarationImpl(this));
   }
-  *aStyle = mDOMDeclaration.get();
-  NS_ADDREF(*aStyle);
-  return NS_OK;
+  return mDOMDeclaration.get();
 }
 
 NS_IMETHODIMP
@@ -1256,11 +1261,10 @@ StyleRule::StyleRule(nsCSSSelectorList* aSelector,
                      Declaration* aDeclaration,
                      uint32_t aLineNumber,
                      uint32_t aColumnNumber)
-  : Rule(aLineNumber, aColumnNumber),
-    mSelector(aSelector),
-    mDeclaration(aDeclaration)
+  : BindingStyleRule(aLineNumber, aColumnNumber)
+  , mSelector(aSelector)
+  , mDeclaration(aDeclaration)
 {
-  SetIsNotDOMBinding();
   NS_PRECONDITION(aDeclaration, "must have a declaration");
 
   mDeclaration->SetOwningRule(this);
@@ -1268,11 +1272,10 @@ StyleRule::StyleRule(nsCSSSelectorList* aSelector,
 
 // for |Clone|
 StyleRule::StyleRule(const StyleRule& aCopy)
-  : Rule(aCopy),
-    mSelector(aCopy.mSelector ? aCopy.mSelector->Clone() : nullptr),
-    mDeclaration(new Declaration(*aCopy.mDeclaration))
+  : BindingStyleRule(aCopy)
+  , mSelector(aCopy.mSelector ? aCopy.mSelector->Clone() : nullptr)
+  , mDeclaration(new Declaration(*aCopy.mDeclaration))
 {
-  SetIsNotDOMBinding();
   mDeclaration->SetOwningRule(this);
   // rest is constructed lazily on existing data
 }
@@ -1301,7 +1304,6 @@ NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(StyleRule)
   else
   NS_INTERFACE_MAP_ENTRY(nsICSSStyleRuleDOMWrapper)
   NS_INTERFACE_MAP_ENTRY(nsIDOMCSSStyleRule)
-  NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(CSSStyleRule)
 NS_INTERFACE_MAP_END_INHERITING(Rule)
 
 NS_IMPL_ADDREF_INHERITED(StyleRule, Rule)
@@ -1496,12 +1498,5 @@ StyleRule::SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
   return n;
 }
 
-/* virtual */ JSObject*
-StyleRule::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
-{
-  NS_NOTREACHED("We called SetIsNotDOMBinding() in our constructor");
-  return nullptr;
-}
-
 } // namespace css
 } // namespace mozilla
diff --git a/layout/style/StyleRule.h b/layout/style/StyleRule.h
index 55ec693a38..ba10542c78 100644
--- a/layout/style/StyleRule.h
+++ b/layout/style/StyleRule.h
@@ -14,7 +14,7 @@
 #include "mozilla/Attributes.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/UniquePtr.h"
-#include "mozilla/css/Rule.h"
+#include "mozilla/BindingStyleRule.h"
 
 #include "nsString.h"
 #include "nsCOMPtr.h"
@@ -325,7 +325,7 @@ namespace css {
 
 class Declaration;
 
-class StyleRule final : public Rule
+class StyleRule final : public BindingStyleRule
                       , public nsICSSStyleRuleDOMWrapper
 {
  public:
@@ -350,6 +350,7 @@ public:
   // WebIDL interface
   uint16_t Type() const override;
   void GetCssTextImpl(nsAString& aCssText) const override;
+  virtual nsICSSDeclaration* Style() override;
 
   // null for style attribute
   nsCSSSelectorList* Selector() { return mSelector; }
@@ -369,8 +370,6 @@ public:
 
   virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const override;
 
-  virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
-
 private:
   ~StyleRule();
 
diff --git a/layout/style/moz.build b/layout/style/moz.build
index 7239526aa8..1212a92d10 100644
--- a/layout/style/moz.build
+++ b/layout/style/moz.build
@@ -74,6 +74,7 @@ EXPORTS += [
 
 EXPORTS.mozilla += [
     'AnimationCollection.h',
+    'BindingStyleRule.h',
     'CSSEnabledState.h',
     'CSSStyleSheet.h',
     'CSSVariableDeclarations.h',
@@ -177,10 +178,18 @@ UNIFIED_SOURCES += [
     'SVGAttrAnimationRuleProcessor.cpp',
 ]
 
-# nsCSSRuleProcessor.cpp needs to be built separately because it uses plarena.h.
-# nsLayoutStylesheetCache.cpp needs to be built separately because it uses
+# - BindingStyleRule.cpp doesn't necessarily need to be built separately,
+# however, it may shift unified build boundaries, causing
+# the Unified CPP containing it to include nsStyleCoord.cpp, which
+# includes, via nsStyleCoord.h, <type_traits>, which ends up including
+# <xutility>, which fails in much the way described in
+# <https://bugzilla.mozilla.org/show_bug.cgi?id=1331102>.
+# - nsCSSRuleProcessor.cpp needs to be built separately because it uses
+# plarena.h.
+# - nsLayoutStylesheetCache.cpp needs to be built separately because it uses
 # nsExceptionHandler.h, which includes windows.h.
 SOURCES += [
+    'BindingStyleRule.cpp',
     'nsCSSRuleProcessor.cpp',
     'nsLayoutStylesheetCache.cpp',
 ]
diff --git a/layout/style/nsICSSStyleRuleDOMWrapper.h b/layout/style/nsICSSStyleRuleDOMWrapper.h
index 038cca0868..f2a3b6ccc9 100644
--- a/layout/style/nsICSSStyleRuleDOMWrapper.h
+++ b/layout/style/nsICSSStyleRuleDOMWrapper.h
@@ -18,6 +18,11 @@
 #define NS_ICSS_STYLE_RULE_DOM_WRAPPER_IID \
 {0xcee1bbb6, 0x0a32, 0x4cf3, {0x8d, 0x42, 0xba, 0x39, 0x38, 0xe9, 0xec, 0xaa}}
 
+namespace mozilla {
+namespace css {
+class StyleRule;
+} // namespace css
+} // namespace mozilla
 
 class nsICSSStyleRuleDOMWrapper : public nsIDOMCSSStyleRule {
 public: