Adding a <media> into an inactive document should not crash.

Bug: 1092889
Test: html/semantics/embedded-content/the-audio-element/audio-appendChild-to-inactive-document-crash.html
Change-Id: I14d78db39b74d4593f3ed71b8440ca108fafdd0a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2247120
Commit-Queue: Kentaro Hara <haraken@chromium.org>
Auto-Submit: Nate Chapin <japhet@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#779148}

third_party/blink/renderer/core/frame/local_dom_window.cc

@@ -380,8 +380,8 @@ const SecurityContext& LocalDOMWindow::GetSecurityContext() const {
 
 bool LocalDOMWindow::CanExecuteScripts(
     ReasonForCallingCanExecuteScripts reason) {
-  DCHECK(GetFrame())
-      << "you are querying canExecuteScripts on a non-attached Window.";
+  if (!GetFrame())
+    return false;
 
   // Normally, scripts are not allowed in sandboxed contexts that disallow them.
   // However, there is an exception for cases when the script should bypass the

third_party/blink/web_tests/external/wpt/html/semantics/embedded-content/the-audio-element/audio-appendChild-to-inactive-document-crash.html

+<iframe id=i></iframe>
+<script>
+var doc = i.contentDocument.cloneNode();
+i.remove();
+doc.appendChild(document.createElement("audio"));
+</script>