2 files changed, 14 insertions, 0 deletions
diff --git a/toolkit/components/windowwatcher/nsIOpenWindowInfo.idl b/toolkit/components/windowwatcher/nsIOpenWindowInfo.idl
index a8347c5a1a..c0edb18536 100644
--- a/toolkit/components/windowwatcher/nsIOpenWindowInfo.idl
+++ b/toolkit/components/windowwatcher/nsIOpenWindowInfo.idl
@@ -74,4 +74,10 @@ interface nsIOpenWindowInfo : nsISupports {
   /* Callback to invoke when the browsing context for a new window is ready. */
   [notxpcom, nostdcall]
   nsIBrowsingContextReadyCallback browsingContextReadyCallback();
+
+  /**
+   * When creating a window fails, we will be called to notify an error via
+   * callback. If no callback, do nothing.
+   */
+  void cancel();
 };
diff --git a/toolkit/components/windowwatcher/nsOpenWindowInfo.cpp b/toolkit/components/windowwatcher/nsOpenWindowInfo.cpp
index 4374090075..042ee45f4e 100644
--- a/toolkit/components/windowwatcher/nsOpenWindowInfo.cpp
+++ b/toolkit/components/windowwatcher/nsOpenWindowInfo.cpp
@@ -57,6 +57,14 @@ nsOpenWindowInfo::BrowsingContextReadyCallback() {
   return mBrowsingContextReadyCallback;
 }
 
+NS_IMETHODIMP nsOpenWindowInfo::Cancel() {
+  if (mBrowsingContextReadyCallback) {
+    mBrowsingContextReadyCallback->BrowsingContextReady(nullptr);
+    mBrowsingContextReadyCallback = nullptr;
+  }
+  return NS_OK;
+}
+
 NS_IMPL_ISUPPORTS(nsBrowsingContextReadyCallback,
                   nsIBrowsingContextReadyCallback)