4 files changed, 99 insertions, 0 deletions
diff --git a/testing/crashtest/crashtests.list b/testing/crashtest/crashtests.list
index a7c539daca..30d6bb8f8f 100644
--- a/testing/crashtest/crashtests.list
+++ b/testing/crashtest/crashtests.list
@@ -83,3 +83,6 @@ include ../../widget/crashtests/crashtests.list
 include ../../widget/gtk/crashtests/crashtests.list
 
 include ../../xpcom/string/crashtests/crashtests.list
+
+# Tests that must be run at the very end of all other crashtests.
+include final/crashtests.list
diff --git a/testing/crashtest/final/1419902.html b/testing/crashtest/final/1419902.html
new file mode 100644
index 0000000000..9fa9149564
--- /dev/null
+++ b/testing/crashtest/final/1419902.html
@@ -0,0 +1,34 @@
+<html>
+  <head>
+    <script>
+      // Note that despite what it looks like this test does leave windows open
+      // after the test finishes. That's because some of the window.open calls
+      // trigger an exception but still open a window. Because of the
+      // exception, winsToClose.push is not executed and we have no reference
+      // to the window. So far there is no known way to get a reference to it.
+      // It was also tried to give each opened windowed a named target, save
+      // that list of targets, and use window.open("", targetname) to get a
+      // reference to the window. That also doesn't work because either the
+      // window.open calls never end and this page never loads, or if it does
+      // load after a finite time then still some windows are left open for
+      // some reason.
+      var winsToClose = []
+      onbeforeunload = function() {
+        for (let win of winsToClose) {
+          if (win) {
+            win.close();
+          }
+        }
+      };
+      for (let i = 0; i < 38; i++) {
+        customElements.define("custom-element_0", class extends HTMLElement {
+          constructor() {
+            try { o1 = document.createElement("custom-element_0") } catch (e) {}
+            try { winsToClose.push(window.open("javascript:'<html><body>dummy</body></html>';")); } catch (e) {}
+          }
+        })
+        try { o3 = document.createElement("custom-element_0") } catch (e) {}
+      }
+    </script>
+  </head>
+</html>
diff --git a/testing/crashtest/final/1758199-1.html b/testing/crashtest/final/1758199-1.html
new file mode 100644
index 0000000000..3f7c9227a4
--- /dev/null
+++ b/testing/crashtest/final/1758199-1.html
@@ -0,0 +1,54 @@
+<html class="reftest-wait">
+<script>
+let pp;
+let documentElements = [];
+documentElements.push(document.documentElement);
+
+window.onload = () => {
+  documentElements.push(document.documentElement);
+
+  let o = document.getElementById('a')
+  o.parentNode.appendChild(o)
+  pp = SpecialPowers.wrap(self).printPreview();
+  pp?.print()
+  window.requestIdleCallback(() => {
+    documentElements.push(document.documentElement);
+
+    document.write('');
+
+    setTimeout(finish, 100);
+  });
+}
+
+function finish() {
+
+  // The printPreview call above actually opens two print preview windows
+  // because the <embed src='#'> below causes a second one to open. At least
+  // we close the one window we can access, not sure if there is a way to get
+  // ahold of the other window to close it. So this test leaves a window open
+  // after it finishes.
+  try { pp.close(); } catch (e) {}
+
+  if (document.documentElement) {
+    try { document.documentElement.className = ""; } catch (e) {}
+  }
+
+  // The documentElement that the reftest harness looks at to determine if the
+  // test is done is not what document.documentElement points to when this code
+  // is run. So we save all the document.documentElement's we encounter while
+  // running this test and clear all of their class names.
+  for (let de of documentElements) {
+    if (de) {
+      try {
+        de.className = "";
+      } catch (e) {}
+    }
+  }
+}
+</script>
+<style>
+:first-of-type { padding-block-start: 99% }
+</style>
+<mark id='a'>
+<embed src='#'>
+</html>
diff --git a/testing/crashtest/final/crashtests.list b/testing/crashtest/final/crashtests.list
new file mode 100644
index 0000000000..d56eb5a984
--- /dev/null
+++ b/testing/crashtest/final/crashtests.list
@@ -0,0 +1,8 @@
+# These are tests that open windows and don't close them after the test
+# finishes because there doesn't seem to be a way to close the windows. We run
+# them here after all other crashtests so that the left open windows don't
+# occlude the reftest window, and hence stop the compositor and refresh driver
+# ticks from happening.
+
+skip-if(geckoview) skip-if(geckoview&&isDebugBuild) skip-if(AddressSanitizer) skip-if(ThreadSanitizer) pref(dom.disable_open_during_load,false) load 1419902.html # skip Bug 1419902. Bug 1563013 for GV+WR. Bug 1524493 GV+debug. Bug 1573281 asan # this comes from dom/base/crashtests/
+skip-if(Android) load 1758199-1.html # printPreview doesn't work on android # this comes from layout/printing/crashtests