Bug 1520372 - Add an ownerElement property to nsITabParent, r=qdot

Differential Revision: https://phabricator.services.mozilla.com/D16713

--HG--
extra : moz-landing-system : lando

dom/interfaces/base/nsITabParent.idl

@@ -6,6 +6,7 @@
 #include "domstubs.idl"
 
 interface nsIPrincipal;
+webidl Element;
 
 [builtinclass, scriptable, uuid(8e49f7b0-1f98-4939-bf91-e9c39cd56434)]
 interface nsITabParent : nsISupports
@@ -81,6 +82,11 @@ interface nsITabParent : nsISupports
    */
   readonly attribute boolean hasBeforeUnload;
 
+  /**
+   * The frame element which currently embeds this nsITabParent object.
+   */
+  readonly attribute Element ownerElement;
+
   /**
    * Notify APZ to start autoscrolling.
    * (aAnchorX, aAnchorY) are the coordinates of the autoscroll anchor,

dom/ipc/TabParent.cpp

@@ -305,6 +305,11 @@ void TabParent::SetOwnerElement(Element* aElement) {
   }
 }
 
+NS_IMETHODIMP TabParent::GetOwnerElement(Element** aElement) {
+  *aElement = do_AddRef(GetOwnerElement()).take();
+  return NS_OK;
+}
+
 void TabParent::AddWindowListeners() {
   if (mFrameElement) {
     if (nsCOMPtr<nsPIDOMWindowOuter> window =