Bug 1492326, add helpers to Element to get nsIDOMXUL* and nsIBrowser interfaces implented by custom elements, r=peterv

dom/base/Element.cpp

@@ -148,6 +148,17 @@
 #include "nsDOMStringMap.h"
 #include "DOMIntersectionObserver.h"
 
+#include "nsIDOMXULButtonElement.h"
+#include "nsIDOMXULContainerElement.h"
+#include "nsIDOMXULControlElement.h"
+#include "nsIDOMXULMenuListElement.h"
+#include "nsIDOMXULMultSelectCntrlEl.h"
+#include "nsIDOMXULRelatedElement.h"
+#include "nsIDOMXULMultSelectCntrlEl.h"
+#include "nsIDOMXULSelectCntrlEl.h"
+#include "nsIDOMXULSelectCntrlItemEl.h"
+#include "nsIBrowser.h"
+
 #include "nsISpeculativeConnect.h"
 #include "nsIIOService.h"
 
@@ -3931,6 +3942,68 @@ void Element::SetCustomElementDefinition(CustomElementDefinition* aDefinition) {
   data->SetCustomElementDefinition(aDefinition);
 }
 
+already_AddRefed<nsIDOMXULButtonElement> Element::AsXULButton() {
+  nsCOMPtr<nsIDOMXULButtonElement> value;
+  GetCustomInterface(getter_AddRefs(value));
+  return value.forget();
+}
+
+already_AddRefed<nsIDOMXULContainerElement> Element::AsXULContainer() {
+  nsCOMPtr<nsIDOMXULContainerElement> value;
+  GetCustomInterface(getter_AddRefs(value));
+  return value.forget();
+}
+
+already_AddRefed<nsIDOMXULContainerItemElement> Element::AsXULContainerItem() {
+  nsCOMPtr<nsIDOMXULContainerItemElement> value;
+  GetCustomInterface(getter_AddRefs(value));
+  return value.forget();
+}
+
+already_AddRefed<nsIDOMXULControlElement> Element::AsXULControl() {
+  nsCOMPtr<nsIDOMXULControlElement> value;
+  GetCustomInterface(getter_AddRefs(value));
+  return value.forget();
+}
+
+already_AddRefed<nsIDOMXULMenuListElement> Element::AsXULMenuList() {
+  nsCOMPtr<nsIDOMXULMenuListElement> value;
+  GetCustomInterface(getter_AddRefs(value));
+  return value.forget();
+}
+
+already_AddRefed<nsIDOMXULMultiSelectControlElement>
+Element::AsXULMultiSelectControl() {
+  nsCOMPtr<nsIDOMXULMultiSelectControlElement> value;
+  GetCustomInterface(getter_AddRefs(value));
+  return value.forget();
+}
+
+already_AddRefed<nsIDOMXULRelatedElement> Element::AsXULRelated() {
+  nsCOMPtr<nsIDOMXULRelatedElement> value;
+  GetCustomInterface(getter_AddRefs(value));
+  return value.forget();
+}
+
+already_AddRefed<nsIDOMXULSelectControlElement> Element::AsXULSelectControl() {
+  nsCOMPtr<nsIDOMXULSelectControlElement> value;
+  GetCustomInterface(getter_AddRefs(value));
+  return value.forget();
+}
+
+already_AddRefed<nsIDOMXULSelectControlItemElement>
+Element::AsXULSelectControlItem() {
+  nsCOMPtr<nsIDOMXULSelectControlItemElement> value;
+  GetCustomInterface(getter_AddRefs(value));
+  return value.forget();
+}
+
+already_AddRefed<nsIBrowser> Element::AsBrowser() {
+  nsCOMPtr<nsIBrowser> value;
+  GetCustomInterface(getter_AddRefs(value));
+  return value.forget();
+}
+
 MOZ_DEFINE_MALLOC_SIZE_OF(ServoElementMallocSizeOf)
 MOZ_DEFINE_MALLOC_ENCLOSING_SIZE_OF(ServoElementMallocEnclosingSizeOf)
 

dom/base/Element.h

@@ -63,6 +63,17 @@ class nsDocument;
 class nsDOMStringMap;
 struct ServoNodeData;
 
+class nsIDOMXULButtonElement;
+class nsIDOMXULContainerElement;
+class nsIDOMXULContainerItemElement;
+class nsIDOMXULControlElement;
+class nsIDOMXULMenuListElement;
+class nsIDOMXULMultiSelectControlElement;
+class nsIDOMXULRelatedElement;
+class nsIDOMXULSelectControlElement;
+class nsIDOMXULSelectControlItemElement;
+class nsIBrowser;
+
 namespace mozilla {
 class DeclarationBlock;
 struct MutationClosureData;
@@ -1567,6 +1578,20 @@ class Element : public FragmentOrElement {
   bool UpdateIntersectionObservation(DOMIntersectionObserver* aObserver,
                                      int32_t threshold);
 
+  // A number of methods to cast to various XUL interfaces. They return a
+  // pointer only if the element implements that interface.
+  already_AddRefed<nsIDOMXULButtonElement> AsXULButton();
+  already_AddRefed<nsIDOMXULContainerElement> AsXULContainer();
+  already_AddRefed<nsIDOMXULContainerItemElement> AsXULContainerItem();
+  already_AddRefed<nsIDOMXULControlElement> AsXULControl();
+  already_AddRefed<nsIDOMXULMenuListElement> AsXULMenuList();
+  already_AddRefed<nsIDOMXULMultiSelectControlElement>
+  AsXULMultiSelectControl();
+  already_AddRefed<nsIDOMXULRelatedElement> AsXULRelated();
+  already_AddRefed<nsIDOMXULSelectControlElement> AsXULSelectControl();
+  already_AddRefed<nsIDOMXULSelectControlItemElement> AsXULSelectControlItem();
+  already_AddRefed<nsIBrowser> AsBrowser();
+
  protected:
   /*
    * Named-bools for use with SetAttrAndNotify to make call sites easier to