--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -6041,29 +6041,27 @@ nsGlobalWindow::AlertOrConfirm(bool aAle
     do_GetService("@mozilla.org/prompter;1", &rv);
   if (NS_FAILED(rv)) {
     aError.Throw(rv);
     return false;
   }
 
   nsCOMPtr<nsIPrompt> prompt;
   aError = promptFac->GetPrompt(this, NS_GET_IID(nsIPrompt),
-                                reinterpret_cast<void**>(&prompt));
+                                getter_AddRefs(prompt));
   if (aError.Failed()) {
     return false;
   }
 
   nsCOMPtr<nsIWritablePropertyBag2> promptBag = do_QueryInterface(prompt);
   if (promptBag)
     promptBag->SetPropertyAsBool(NS_LITERAL_STRING("allowTabModal"), allowTabModal);
 
   bool result = false;
-  nsAutoSyncOperation sync(GetCurrentInnerWindowInternal() ? 
-                             GetCurrentInnerWindowInternal()->mDoc :
-                             nullptr);
+  nsAutoSyncOperation sync(mDoc);
   if (ShouldPromptToBlockDialogs()) {
     bool disallowDialog = false;
     nsXPIDLString label;
     nsContentUtils::GetLocalizedString(nsContentUtils::eCOMMON_DIALOG_PROPERTIES,
                                        "ScriptDialogLabel", label);
 
     aError = aAlert ?
                prompt->AlertCheck(title.get(), final.get(), label.get(),
@@ -6158,17 +6156,17 @@ nsGlobalWindow::Prompt(const nsAString& 
     do_GetService("@mozilla.org/prompter;1", &rv);
   if (NS_FAILED(rv)) {
     aError.Throw(rv);
     return;
   }
 
   nsCOMPtr<nsIPrompt> prompt;
   aError = promptFac->GetPrompt(this, NS_GET_IID(nsIPrompt),
-                                reinterpret_cast<void**>(&prompt));
+                                getter_AddRefs(prompt));
   if (aError.Failed()) {
     return;
   }
 
   nsCOMPtr<nsIWritablePropertyBag2> promptBag = do_QueryInterface(prompt);
   if (promptBag)
     promptBag->SetPropertyAsBool(NS_LITERAL_STRING("allowTabModal"), allowTabModal);
 
@@ -6177,19 +6175,17 @@ nsGlobalWindow::Prompt(const nsAString& 
   bool disallowDialog = false;
 
   nsXPIDLString label;
   if (ShouldPromptToBlockDialogs()) {
     nsContentUtils::GetLocalizedString(nsContentUtils::eCOMMON_DIALOG_PROPERTIES,
                                        "ScriptDialogLabel", label);
   }
 
-  nsAutoSyncOperation sync(GetCurrentInnerWindowInternal() ? 
-                             GetCurrentInnerWindowInternal()->mDoc :
-                             nullptr);
+  nsAutoSyncOperation sync(mDoc);
   bool ok;
   aError = prompt->Prompt(title.get(), fixedMessage.get(),
                           &inoutValue, label.get(), &disallowDialog, &ok);
 
   if (disallowDialog) {
     DisableDialogs();
   }