WebSpeech: start() throws if detached iframe

Spec PR: WebAudio/web-speech-api#138

Bug: 384797834
Change-Id: I553842e4427071dacc7693ea6f1f2503cb0cf0dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6237075
Reviewed-by: Evan Liu <[email protected]>
Commit-Queue: Fr <[email protected]>
Reviewed-by: Mason Freed <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1422104}

speech-api/SpeechRecognition-detached-iframe.window.js

@@ -0,0 +1,35 @@
+// META: title=SpeechRecognition in a detached iframe test
+
+test(() => {
+  // Create the iframe and append it to the document.
+  const iframe = document.createElement("iframe");
+  document.body.appendChild(iframe);
+  const frameWindow = iframe.contentWindow;
+
+  // Detach the iframe.
+  iframe.remove();
+
+  assert_equals(
+    undefined,
+    frameWindow.SpeechRecognition || frameWindow.webkitSpeechRecognition,
+  );
+}, "SpeechRecognition constructor does not exist in detached iframes");
+
+test((t) => {
+  // Create the iframe and append it to the document.
+  const iframe = document.createElement("iframe");
+  document.body.appendChild(iframe);
+  const frameWindow = iframe.contentWindow;
+  const frameDOMException = frameWindow.DOMException;
+
+  frameWindow.SpeechRecognition =
+    frameWindow.SpeechRecognition || frameWindow.webkitSpeechRecognition;
+  const speechRecognition = new frameWindow.SpeechRecognition();
+
+  // Detach the iframe.
+  iframe.remove();
+
+  assert_throws_dom("InvalidStateError", frameDOMException, () =>
+    speechRecognition.start(),
+  );
+}, "SpeechRecognition.start() on detached frame throws");