Bug 1704651 - Wait for the right load in ClientOpenWindow. r=asuth

With fission+BFCache, we get a notification for the initial document,
and that fails the same-origin check (because about:blank isn't
same-origin with the opener) so we resolve the promise with null
rather than returning a client.

Instead, wait for the right load to arrive if the top level window
global is the initial document.

Differential Revision: https://phabricator.services.mozilla.com/D112072

dom/clients/manager/ClientOpenWindowUtils.cpp

@@ -83,8 +83,10 @@ class WebProgressListener final : public nsIWebProgressListener,
 
     // Our caller keeps a strong reference, so it is safe to remove the listener
     // from the BrowsingContext's nsIWebProgress.
-    nsCOMPtr<nsIWebProgress> webProgress = browsingContext->GetWebProgress();
-    webProgress->RemoveProgressListener(this);
+    auto RemoveListener = [&] {
+      nsCOMPtr<nsIWebProgress> webProgress = browsingContext->GetWebProgress();
+      webProgress->RemoveProgressListener(this);
+    };
 
     RefPtr<dom::WindowGlobalParent> wgp =
         browsingContext->GetCurrentWindowGlobal();
@@ -93,9 +95,18 @@ class WebProgressListener final : public nsIWebProgressListener,
       rv.ThrowInvalidStateError("Unable to open window");
       mPromise->Reject(rv, __func__);
       mPromise = nullptr;
+      RemoveListener();
       return NS_OK;
     }
 
+    if (NS_WARN_IF(wgp->IsInitialDocument())) {
+      // This is the load of the initial document, which is not the document we
+      // care about for the purposes of checking same-originness of the URL.
+      return NS_OK;
+    }
+
+    RemoveListener();
+
     // Check same origin. If the origins do not match, resolve with null (per
     // step 7.2.7.1 of the openWindow spec).
     nsCOMPtr<nsIScriptSecurityManager> securityManager =
@@ -104,7 +115,7 @@ class WebProgressListener final : public nsIWebProgressListener,
         wgp->DocumentPrincipal()->OriginAttributesRef().mPrivateBrowsingId > 0;
     nsresult rv = securityManager->CheckSameOriginURI(
         wgp->GetDocumentURI(), mBaseURI, false, isPrivateWin);
-    if (NS_FAILED(rv)) {
+    if (NS_WARN_IF(NS_FAILED(rv))) {
       mPromise->Resolve(CopyableErrorResult(), __func__);
       mPromise = nullptr;
       return NS_OK;

dom/serviceworkers/test/openWindow_worker.js

@@ -25,7 +25,7 @@ function testForUrl(url, throwType, clientProperties, resultsArray) {
       } else if (clientProperties) {
         resultsArray.push({
           result: e instanceof WindowClient,
-          message: "openWindow should resolve to a WindowClient",
+          message: `openWindow should resolve to a WindowClient for url ${url}, got ${e}`,
         });
         resultsArray.push({
           result: e.url == clientProperties.url,