Bug 1422197 - Add fast path to get DocGroup in binding code for [CEReactions]

Tag #1375

dom/base/CustomElementRegistry.cpp

@@ -453,6 +453,12 @@ nsISupports* CustomElementRegistry::GetParentObject() const
   return mWindow;
 }
 
+DocGroup*
+CustomElementRegistry::GetDocGroup() const
+{
+  return mWindow ? mWindow->GetDocGroup() : nullptr;
+}
+
 static const char* kLifeCycleCallbackNames[] = {
   "connectedCallback",
   "disconnectedCallback",

dom/base/CustomElementRegistry.h

@@ -27,6 +27,7 @@ struct CustomElementData;
 struct ElementDefinitionOptions;
 class CallbackFunction;
 class CustomElementReaction;
+class DocGroup;
 class Function;
 class Promise;
 
@@ -513,6 +514,8 @@ private:
 public:
   nsISupports* GetParentObject() const;
 
+  DocGroup* GetDocGroup() const;
+
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   void Define(const nsAString& aName, Function& aFunctionConstructor,

dom/base/nsDOMAttributeMap.cpp

@@ -524,3 +524,9 @@ nsDOMAttributeMap::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
 {
   return NamedNodeMapBinding::Wrap(aCx, this, aGivenProto);
 }
+
+DocGroup*
+nsDOMAttributeMap::GetDocGroup() const
+{
+  return mContent ? mContent->OwnerDoc()->GetDocGroup() : nullptr;
+}

dom/base/nsDOMAttributeMap.h

@@ -22,6 +22,11 @@
 
 class nsIAtom;
 class nsIDocument;
+namespace mozilla {
+namespace dom {
+class DocGroup;
+} // namespace dom
+} // namespace mozilla
 
 /**
  * Structure used as a key for caching Attrs in nsDOMAttributeMap's mAttributeCache.
@@ -87,6 +92,7 @@ class nsDOMAttributeMap final : public nsIDOMMozNamedAttrMap
 {
 public:
   typedef mozilla::dom::Attr Attr;
+  typedef mozilla::dom::DocGroup DocGroup;
   typedef mozilla::dom::Element Element;
   typedef mozilla::ErrorResult ErrorResult;
 
@@ -135,6 +141,7 @@ public:
     return mContent;
   }
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
+  DocGroup* GetDocGroup() const;
 
   // WebIDL
   Attr* GetNamedItem(const nsAString& aAttrName);

dom/base/nsDOMTokenList.cpp

@@ -366,6 +366,12 @@ nsDOMTokenList::Stringify(nsAString& aResult)
   mElement->GetAttr(kNameSpaceID_None, mAttrAtom, aResult);
 }
 
+DocGroup*
+nsDOMTokenList::GetDocGroup() const
+{
+  return mElement ? mElement->OwnerDoc()->GetDocGroup() : nullptr;
+}
+
 JSObject*
 nsDOMTokenList::WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto)
 {

dom/base/nsDOMTokenList.h

@@ -22,7 +22,9 @@
 
 namespace mozilla {
 class ErrorResult;
-
+namespace dom {
+class DocGroup;
+} // namespace dom
 } // namespace mozilla
 
 class nsAttrValue;
@@ -35,6 +37,7 @@ class nsDOMTokenList : public nsISupports,
 {
 protected:
   typedef mozilla::dom::Element Element;
+  typedef mozilla::dom::DocGroup DocGroup;
   typedef nsWhitespaceTokenizerTemplate<nsContentUtils::IsHTMLWhitespace>
     WhitespaceTokenizer;
 
@@ -52,6 +55,8 @@ public:
     return mElement;
   }
 
+  DocGroup* GetDocGroup() const;
+
   uint32_t Length();
   void Item(uint32_t aIndex, nsAString& aResult)
   {

dom/base/nsINode.cpp

@@ -3132,3 +3132,9 @@ nsINode::IsStyledByServo() const
   return OwnerDoc()->IsStyledByServo();
 }
 #endif
+
+DocGroup*
+nsINode::GetDocGroup() const
+{
+  return OwnerDoc()->GetDocGroup();
+}

dom/base/nsINode.h

@@ -72,6 +72,7 @@ inline bool IsSpaceCharacter(char aChar) {
 class AccessibleNode;
 struct BoxQuadOptions;
 struct ConvertCoordinateOptions;
+class DocGroup;
 class DOMPoint;
 class DOMQuad;
 class DOMRectReadOnly;
@@ -299,6 +300,7 @@ class nsINode : public mozilla::dom::EventTarget
 public:
   typedef mozilla::dom::BoxQuadOptions BoxQuadOptions;
   typedef mozilla::dom::ConvertCoordinateOptions ConvertCoordinateOptions;
+  typedef mozilla::dom::DocGroup DocGroup;
   typedef mozilla::dom::DOMPoint DOMPoint;
   typedef mozilla::dom::DOMPointInit DOMPointInit;
   typedef mozilla::dom::DOMQuad DOMQuad;
@@ -613,6 +615,11 @@ public:
     return mNodeInfo->NamespaceID() == aNamespace;
   }
 
+  /**
+   * Returns the DocGroup of the "node document" of this node.
+   */
+  DocGroup* GetDocGroup() const;
+
   /**
    * Print a debugger friendly descriptor of this element. This will describe
    * the position of this element in the document.

dom/base/nsRange.cpp

@@ -49,6 +49,12 @@ nsRange::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
   return RangeBinding::Wrap(aCx, this, aGivenProto);
 }
 
+DocGroup*
+nsRange::GetDocGroup() const
+{
+  return mOwner ? mOwner->GetDocGroup() : nullptr;
+}
+
 /******************************************************
  * stack based utilty class for managing monitor
  ******************************************************/

dom/base/nsRange.h

@@ -26,6 +26,7 @@ namespace mozilla {
 class ErrorResult;
 namespace dom {
 struct ClientRectsAndTexts;
+class DocGroup;
 class DocumentFragment;
 class DOMRect;
 class DOMRectList;
@@ -38,6 +39,7 @@ class nsRange final : public nsIDOMRange,
                       public nsWrapperCache
 {
   typedef mozilla::ErrorResult ErrorResult;
+  typedef mozilla::dom::DocGroup DocGroup;
   typedef mozilla::dom::DOMRect DOMRect;
   typedef mozilla::dom::DOMRectList DOMRectList;
 
@@ -280,6 +282,7 @@ public:
 
   nsINode* GetParentObject() const { return mOwner; }
   virtual JSObject* WrapObject(JSContext* cx, JS::Handle<JSObject*> aGivenProto) override final;
+  DocGroup* GetDocGroup() const;
 
 private:
   // no copy's or assigns

dom/bindings/BindingUtils.cpp

@@ -3406,28 +3406,6 @@ GetDesiredProto(JSContext* aCx, const JS::CallArgs& aCallArgs,
   return true;
 }
 
-CustomElementReactionsStack*
-GetCustomElementReactionsStack(JS::Handle<JSObject*> aObj)
-{
-  // This might not be the right object, if there are wrappers. Unwrap if we can.
-  JSObject* obj = js::CheckedUnwrap(aObj);
-  if (!obj) {
-    return nullptr;
-  }
-
-  nsGlobalWindow* window = xpc::WindowGlobalOrNull(obj);
-  if (!window) {
-    return nullptr;
-  }
-
-  DocGroup* docGroup = window->AsInner()->GetDocGroup();
-  if (!docGroup) {
-    return nullptr;
-  }
-
-  return docGroup->CustomElementReactionsStack();
-}
-
 // https://html.spec.whatwg.org/multipage/dom.html#htmlconstructor
 already_AddRefed<nsGenericHTMLElement>
 CreateHTMLElement(const GlobalObject& aGlobal, const JS::CallArgs& aCallArgs,

dom/bindings/BindingUtils.h

@@ -3422,12 +3422,6 @@ bool
 GetDesiredProto(JSContext* aCx, const JS::CallArgs& aCallArgs,
                 JS::MutableHandle<JSObject*> aDesiredProto);
 
-// Get the CustomElementReactionsStack for the docgroup of the global
-// of the underlying object of aObj.  This can be null if aObj can't
-// be CheckUnwrapped, or if the global of the result has no docgroup
-// (e.g. because it's not a Window global).
-CustomElementReactionsStack*
-GetCustomElementReactionsStack(JS::Handle<JSObject*> aObj);
 // This function is expected to be called from the constructor function for an
 // HTML element interface; the global/callargs need to be whatever was passed to
 // that constructor function.

dom/bindings/Codegen.py

@@ -7680,14 +7680,14 @@ class CGPerSignatureCall(CGThing):
 
         if (idlNode.getExtendedAttribute('CEReactions') is not None and
             not getter):
-            cgThings.append(CGGeneric(fill(
+            cgThings.append(CGGeneric(dedent(
                 """
-                CustomElementReactionsStack* reactionsStack = GetCustomElementReactionsStack(${obj});
                   Maybe<AutoCEReaction> ceReaction;
-                if (reactionsStack) {
+                  DocGroup* docGroup = self->GetDocGroup();
-                    ceReaction.emplace(reactionsStack, cx);
+                  if (docGroup) {
+                    ceReaction.emplace(docGroup->CustomElementReactionsStack(), cx);
                 }
-                """, obj=objectName)))
+                """)))
 
         # If this is a method that was generated by a maplike/setlike
         # interface, use the maplike/setlike generator to fill in the body.
@@ -13786,6 +13786,8 @@ class CGForwardDeclarations(CGWrapper):
             builder.add(d.nativeType + "Atoms", isStruct=True)
             for t in getTypesFromDescriptor(d):
                 builder.forwardDeclareForType(t, config)
+            if d.hasCEReactions():
+                builder.addInMozillaDom("DocGroup")
 
         for d in dictionaries:
             if len(d.members) > 0:
@@ -13857,18 +13859,15 @@ class CGBindingRoot(CGThing):
             iface = desc.interface
             return any(m.getExtendedAttribute("Deprecated") for m in iface.members + [iface])
 
-        def descriptorHasCEReactions(desc):
-            iface = desc.interface
-            return any(m.getExtendedAttribute("CEReactions") for m in iface.members + [iface])
-
         bindingHeaders["nsIDocument.h"] = any(
             descriptorDeprecated(d) for d in descriptors)
         bindingHeaders["mozilla/Preferences.h"] = any(
             descriptorRequiresPreferences(d) for d in descriptors)
         bindingHeaders["mozilla/dom/DOMJSProxyHandler.h"] = any(
             d.concrete and d.proxy for d in descriptors)
-        bindingHeaders["mozilla/dom/CustomElementRegistry.h"] = any(
+        hasCEReactions = any(d.hasCEReactions() for d in descriptors)
-            descriptorHasCEReactions(d) for d in descriptors)
+        bindingHeaders["mozilla/dom/CustomElementRegistry.h"] = hasCEReactions
+        bindingHeaders["mozilla/dom/DocGroup.h"] = hasCEReactions
 
         def descriptorHasChromeOnly(desc):
             ctor = desc.interface.ctor()
@@ -14704,6 +14703,12 @@ class CGBindingImplClass(CGClass):
                                             breakAfterReturnDecl=" ",
                                             override=descriptor.wrapperCache,
                                             body=self.getWrapObjectBody()))
+        if descriptor.hasCEReactions():
+            self.methodDecls.insert(0,
+                                    ClassMethod("GetDocGroup", "DocGroup*", [],
+                                                const=True,
+                                                breakAfterReturnDecl=" ",
+                                                body=self.getGetDocGroupBody()))
         if wantGetParent:
             self.methodDecls.insert(0,
                                     ClassMethod("GetParentObject",
@@ -14724,6 +14729,9 @@ class CGBindingImplClass(CGClass):
     def getGetParentObjectBody(self):
         return None
 
+    def getGetDocGroupBody(self):
+        return None
+
     def deps(self):
         return self._deps
 
@@ -14863,6 +14871,8 @@ class CGExampleRoot(CGThing):
         self.root = CGNamespace.build(["mozilla", "dom"], self.root)
 
         builder = ForwardDeclarationBuilder()
+        if descriptor.hasCEReactions():
+            builder.addInMozillaDom("DocGroup")
         for member in descriptor.interface.members:
             if not member.isAttr() and not member.isMethod():
                 continue
@@ -15174,7 +15184,7 @@ class CGJSImplClass(CGBindingImplClass):
 
             private:
               RefPtr<${jsImplName}> mImpl;
-              nsCOMPtr<nsISupports> mParent;
+              nsCOMPtr<nsIGlobalObject> mParent;
 
             """,
             isupportsDecl=isupportsDecl,
@@ -15253,6 +15263,16 @@ class CGJSImplClass(CGBindingImplClass):
     def getGetParentObjectBody(self):
         return "return mParent;\n"
 
+    def getGetDocGroupBody(self):
+        return dedent(
+            """
+            nsCOMPtr<nsPIDOMWindowInner> window = do_QueryInterface(mParent);
+            if (!window) {
+              return nullptr;
+            }
+            return window->GetDocGroup();
+            """)
+
     def getCreateFromExistingBody(self):
         # XXXbz we could try to get parts of this (e.g. the argument
         # conversions) auto-generated by somehow creating an IDLMethod and

dom/bindings/Configuration.py

@@ -631,6 +631,9 @@ class Descriptor(DescriptorProvider):
                  not self.interface.isExposedInWindow()) or
                 self.interface.isExposedInSomeButNotAllWorkers())
 
+    def hasCEReactions(self):
+        return any(m.getExtendedAttribute("CEReactions") for m in self.interface.members)
+
     def isExposedConditionally(self):
         return (self.interface.isExposedConditionally() or
                 self.interface.isExposedInSomeButNotAllWorkers())

dom/bindings/test/TestBindingHeader.h

@@ -21,6 +21,7 @@
 // this one for it, for ParentDict. Hopefully it won't begin to rely on it in more fundamental ways.
 namespace mozilla {
 namespace dom {
+class DocGroup;
 class TestExternalInterface;
 class Promise;
 } // namespace dom
@@ -46,8 +47,9 @@ public:
   NS_DECLARE_STATIC_IID_ACCESSOR(NS_RENAMED_INTERFACE_IID)
   NS_DECL_ISUPPORTS
 
-  // We need a GetParentObject to make binding codegen happy
+  // We need a GetParentObject and GetDocGroup to make binding codegen happy
   virtual nsISupports* GetParentObject();
+  DocGroup* GetDocGroup() const;
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(nsRenamedInterface, NS_RENAMED_INTERFACE_IID)
@@ -64,8 +66,9 @@ public:
   NS_DECLARE_STATIC_IID_ACCESSOR(NS_INDIRECTLY_IMPLEMENTED_INTERFACE_IID)
   NS_DECL_ISUPPORTS
 
-  // We need a GetParentObject to make binding codegen happy
+  // We need a GetParentObject and GetDocGroup to make binding codegen happy
   virtual nsISupports* GetParentObject();
+  DocGroup* GetDocGroup() const;
 
   bool IndirectlyImplementedProperty();
   void IndirectlyImplementedProperty(bool);

dom/html/HTMLOptionsCollection.cpp

@@ -239,6 +239,12 @@ HTMLOptionsCollection::GetParentObject()
   return mSelect;
 }
 
+DocGroup*
+HTMLOptionsCollection::GetDocGroup() const
+{
+  return mSelect ? mSelect->GetDocGroup() : nullptr;
+}
+
 NS_IMETHODIMP
 HTMLOptionsCollection::NamedItem(const nsAString& aName,
                                  nsIDOMNode** aReturn)

dom/html/HTMLOptionsCollection.h

@@ -23,6 +23,7 @@ class nsIDOMHTMLOptionElement;
 namespace mozilla {
 namespace dom {
 
+class DocGroup;
 class HTMLElementOrLong;
 class HTMLOptionElementOrHTMLOptGroupElement;
 class HTMLSelectElement;
@@ -62,6 +63,7 @@ public:
 
   virtual Element* GetElementAt(uint32_t aIndex) override;
   virtual nsINode* GetParentObject() override;
+  DocGroup* GetDocGroup() const;
 
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(HTMLOptionsCollection,
                                                          nsIHTMLCollection)

dom/html/nsDOMStringMap.cpp

@@ -62,6 +62,12 @@ nsDOMStringMap::~nsDOMStringMap()
   }
 }
 
+DocGroup*
+nsDOMStringMap::GetDocGroup() const
+{
+  return mElement ? mElement->GetDocGroup() : nullptr;
+}
+
 /* virtual */
 JSObject*
 nsDOMStringMap::WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto)

dom/html/nsDOMStringMap.h

@@ -16,6 +16,9 @@
 
 namespace mozilla {
 class ErrorResult;
+namespace dom {
+class DocGroup;
+} // namespace dom
 } // namespace mozilla
 
 class nsDOMStringMap : public nsStubMutationObserver,
@@ -32,6 +35,8 @@ public:
     return mElement;
   }
 
+  mozilla::dom::DocGroup* GetDocGroup() const;
+
   explicit nsDOMStringMap(mozilla::dom::Element* aElement);
 
   // WebIDL API

dom/xslt/xslt/txMozillaXSLTProcessor.cpp

@@ -1284,6 +1284,11 @@ txMozillaXSLTProcessor::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenP
     return XSLTProcessorBinding::Wrap(aCx, this, aGivenProto);
 }
 
+DocGroup*
+txMozillaXSLTProcessor::GetDocGroup() const
+{
+    return mStylesheetDocument ? mStylesheetDocument->GetDocGroup() : nullptr;
+}
 
 /* static */ already_AddRefed<txMozillaXSLTProcessor>
 txMozillaXSLTProcessor::Constructor(const GlobalObject& aGlobal,

dom/xslt/xslt/txMozillaXSLTProcessor.h

@@ -29,6 +29,7 @@ class txIGlobalParameter;
 namespace mozilla {
 namespace dom {
 
+class DocGroup;
 class Document;
 class DocumentFragment;
 class GlobalObject;
@@ -103,6 +104,8 @@ public:
         return mOwner;
     }
 
+    mozilla::dom::DocGroup* GetDocGroup() const;
+
     static already_AddRefed<txMozillaXSLTProcessor>
     Constructor(const mozilla::dom::GlobalObject& aGlobal,
                 mozilla::ErrorResult& aRv);

layout/generic/Selection.h

@@ -31,6 +31,9 @@ class nsHTMLCopyEncoder;
 namespace mozilla {
 class ErrorResult;
 struct AutoPrepareFocusRange;
+namespace dom {
+class DocGroup;
+} // namespace dom
 } // namespace mozilla
 
 struct RangeData
@@ -73,6 +76,7 @@ public:
   nsresult EndBatchChangesInternal(int16_t aReason = nsISelectionListener::NO_REASON);
 
   nsIDocument* GetParentObject() const;
+  DocGroup* GetDocGroup() const;
 
   // utility methods for scrolling the selection into view
   nsPresContext* GetPresContext() const;

layout/generic/nsSelection.cpp

@@ -3521,6 +3521,18 @@ Selection::GetParentObject() const
   return nullptr;
 }
 
+DocGroup*
+Selection::GetDocGroup() const
+{
+  nsIPresShell* shell = GetPresShell();
+  if (!shell) {
+    return nullptr;
+  }
+
+  nsIDocument* doc = shell->GetDocument();
+  return doc ? doc->GetDocGroup() : nullptr;
+}
+
 NS_IMPL_CYCLE_COLLECTION_CLASS(Selection)
 
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(Selection)

layout/style/StyleRule.cpp

@@ -1078,6 +1078,16 @@ public:
     return mRule ? mRule->GetDocument() : nullptr;
   }
 
+  virtual DocGroup* GetDocGroup() const override
+  {
+    if (!mRule) {
+      return nullptr;
+    }
+
+    nsIDocument* document = mRule->GetDocument();
+    return document ? document->GetDocGroup() : nullptr;
+  }
+
   friend class css::DOMCSSStyleRule;
 
 protected:

layout/style/nsCSSRules.cpp

@@ -1515,6 +1515,13 @@ nsCSSFontFaceStyleDecl::GetParentObject()
   return ContainingRule()->GetDocument();
 }
 
+DocGroup*
+nsCSSFontFaceStyleDecl::GetDocGroup() const
+{
+  nsIDocument* document = ContainingRule()->GetDocument();
+  return document ? document->GetDocGroup() : nullptr;
+}
+
 JSObject*
 nsCSSFontFaceStyleDecl::WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto)
 {
@@ -1991,6 +1998,17 @@ nsCSSKeyframeStyleDeclaration::GetParentObject()
   return mRule ? mRule->GetDocument() : nullptr;
 }
 
+DocGroup*
+nsCSSKeyframeStyleDeclaration::GetDocGroup() const
+{
+  if (!mRule) {
+    return nullptr;
+  }
+
+  nsIDocument* document = mRule->GetDocument();
+  return document ? document->GetDocGroup() : nullptr;
+}
+
 // -------------------------------------------
 // nsCSSKeyframeRule
 //
@@ -2538,6 +2556,17 @@ nsCSSPageStyleDeclaration::GetParentObject()
   return mRule ? mRule->GetDocument() : nullptr;
 }
 
+DocGroup*
+nsCSSPageStyleDeclaration::GetDocGroup() const
+{
+  if (!mRule) {
+    return nullptr;
+  }
+
+  nsIDocument* document = mRule->GetDocument();
+  return document ? document->GetDocGroup() : nullptr;
+}
+
 // -------------------------------------------
 // nsCSSPageRule
 //

layout/style/nsCSSRules.h

@@ -39,6 +39,11 @@ class nsMediaList;
 
 namespace mozilla {
 
+namespace dom {
+class DocGroup;
+class DocGroup;
+} // namespace dom
+
 class ErrorResult;
 
 namespace css {
@@ -209,6 +214,7 @@ public:
   using nsICSSDeclaration::GetPropertyCSSValue;
 
   virtual nsINode *GetParentObject() override;
+  virtual mozilla::dom::DocGroup* GetDocGroup() const override;
   virtual void IndexedGetter(uint32_t aIndex, bool& aFound, nsAString& aPropName) override;
 
   nsresult GetPropertyValue(nsCSSFontDesc aFontDescID,
@@ -366,6 +372,7 @@ public:
                                                          nsICSSDeclaration)
 
   virtual nsINode* GetParentObject() override;
+  virtual mozilla::dom::DocGroup* GetDocGroup() const override;
 
 protected:
   virtual ~nsCSSKeyframeStyleDeclaration();
@@ -496,6 +503,7 @@ public:
                                                          nsICSSDeclaration)
 
   virtual nsINode *GetParentObject() override;
+  virtual mozilla::dom::DocGroup* GetDocGroup() const override;
 
 protected:
   virtual ~nsCSSPageStyleDeclaration();

layout/style/nsComputedDOMStyle.h

@@ -27,6 +27,7 @@
 
 namespace mozilla {
 namespace dom {
+class DocGroup;
 class Element;
 } // namespace dom
 struct ComputedGridTrackInfo;
@@ -84,6 +85,11 @@ public:
     return mElement;
   }
 
+  virtual mozilla::dom::DocGroup* GetDocGroup() const override
+  {
+    return mElement ? mElement->GetDocGroup() : nullptr;
+  }
+
   static already_AddRefed<nsStyleContext>
   GetStyleContextForElement(mozilla::dom::Element* aElement, nsIAtom* aPseudo,
                             nsIPresShell* aPresShell,

layout/style/nsDOMCSSAttrDeclaration.cpp

@@ -178,6 +178,12 @@ nsDOMCSSAttributeDeclaration::GetParentObject()
   return mElement;
 }
 
+/* virtual */ DocGroup*
+nsDOMCSSAttributeDeclaration::GetDocGroup() const
+{
+  return mElement ? mElement->OwnerDoc()->GetDocGroup() : nullptr;
+}
+
 NS_IMETHODIMP
 nsDOMCSSAttributeDeclaration::SetPropertyValue(const nsCSSPropertyID aPropID,
                                                const nsAString& aValue)

layout/style/nsDOMCSSAttrDeclaration.h

@@ -35,6 +35,7 @@ public:
   NS_IMETHOD GetParentRule(nsIDOMCSSRule **aParent) override;
 
   virtual nsINode* GetParentObject() override;
+  virtual DocGroup* GetDocGroup() const override;
 
   NS_IMETHOD SetPropertyValue(const nsCSSPropertyID aPropID,
                               const nsAString& aValue) override;

layout/style/nsICSSDeclaration.h

@@ -31,6 +31,11 @@
 #include "nsCOMPtr.h"
 
 class nsINode;
+namespace mozilla {
+namespace dom {
+class DocGroup;
+} // namespace dom
+} // namespace mozilla
 
 // dbeabbfa-6cb3-4f5c-aec2-dd558d9d681f
 #define NS_ICSSDECLARATION_IID \
@@ -62,6 +67,7 @@ public:
                               const nsAString& aValue) = 0;
 
   virtual nsINode *GetParentObject() = 0;
+  virtual mozilla::dom::DocGroup* GetDocGroup() const = 0;
 
   // Also have to declare all the nsIDOMCSSStyleDeclaration methods,
   // since we want to be able to call them from the WebIDL versions.