Bug 1539959 - Don't send WindowGlobalChild constructors when parent BrowsingContext has already been closed, r=farre

Differential Revision: https://phabricator.services.mozilla.com/D27365

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

dom/ipc/WindowGlobalChild.cpp

@@ -60,6 +60,13 @@ already_AddRefed<WindowGlobalChild> WindowGlobalChild::Create(
 
   RefPtr<WindowGlobalChild> wgc = new WindowGlobalChild(aWindow, bc);
 
+  // If we have already closed our browsing context, return a pre-closed
+  // WindowGlobalChild actor.
+  if (bc->GetClosed()) {
+    wgc->ActorDestroy(FailedConstructor);
+    return wgc.forget();
+  }
+
   WindowGlobalInit init(principal, aWindow->GetDocumentURI(), bc,
                         wgc->mInnerWindowId, wgc->mOuterWindowId);