1 files changed, 108 insertions, 0 deletions
diff --git a/dom/media/mediacontrol/tests/browser/browser_remove_controllable_media_for_active_controller.js b/dom/media/mediacontrol/tests/browser/browser_remove_controllable_media_for_active_controller.js
new file mode 100644
index 0000000000..a0aa5af4e9
--- /dev/null
+++ b/dom/media/mediacontrol/tests/browser/browser_remove_controllable_media_for_active_controller.js
@@ -0,0 +1,108 @@
+const PAGE_URL =
+  "https://example.com/browser/dom/media/mediacontrol/tests/browser/file_non_autoplay.html";
+
+const testVideoId = "video";
+
+add_task(async function setupTestingPref() {
+  await SpecialPowers.pushPrefEnv({
+    set: [["media.mediacontrol.testingevents.enabled", true]],
+  });
+});
+
+/**
+ * If an active controller has an active media session, then it can still be
+ * controlled via media key even if there is no controllable media presents.
+ * As active media session could still create other controllable media in its
+ * action handler, it should still receive media key. However, if a controller
+ * doesn't have an active media session, then it won't be controlled via media
+ * key when no controllable media presents.
+ */
+add_task(
+  async function testControllerWithActiveMediaSessionShouldStillBeActiveWhenNoControllableMediaPresents() {
+    info(`open media page`);
+    const tab = await createLoadedTabWrapper(PAGE_URL);
+
+    info(`play media would activate controller and media session`);
+    await setupMediaSession(tab);
+    await playMedia(tab, testVideoId);
+    await checkOrWaitControllerBecomesActive(tab);
+
+    info(`remove playing media so we don't have any controllable media now`);
+    await Promise.all([
+      new Promise(r => (tab.controller.onplaybackstatechange = r)),
+      removePlayingMedia(tab),
+    ]);
+
+    info(`despite that, controller should still be active`);
+    await checkOrWaitControllerBecomesActive(tab);
+
+    info(`active media session can still receive media key`);
+    await ensureActiveMediaSessionReceivedMediaKey(tab);
+
+    info(`remove tab`);
+    await tab.close();
+  }
+);
+
+add_task(
+  async function testControllerWithoutActiveMediaSessionShouldBecomeInactiveWhenNoControllableMediaPresents() {
+    info(`open media page`);
+    const tab = await createLoadedTabWrapper(PAGE_URL);
+
+    info(`play media would activate controller`);
+    await playMedia(tab, testVideoId);
+    await checkOrWaitControllerBecomesActive(tab);
+
+    info(
+      `remove playing media so we don't have any controllable media, which would deactivate controller`
+    );
+    await Promise.all([
+      new Promise(r => (tab.controller.ondeactivated = r)),
+      removePlayingMedia(tab),
+    ]);
+
+    info(`remove tab`);
+    await tab.close();
+  }
+);
+
+/**
+ * The following are helper functions.
+ */
+function setupMediaSession(tab) {
+  return SpecialPowers.spawn(tab.linkedBrowser, [], _ => {
+    // except `play/pause/stop`, set an action handler for arbitrary key in
+    // order to later verify if the session receives that media key by listening
+    // to session's `onpositionstatechange`.
+    content.navigator.mediaSession.setActionHandler("seekforward", _ => {
+      content.navigator.mediaSession.setPositionState({
+        duration: 60,
+      });
+    });
+  });
+}
+
+async function ensureActiveMediaSessionReceivedMediaKey(tab) {
+  const controller = tab.linkedBrowser.browsingContext.mediaController;
+  const positionChangePromise = new Promise(
+    r => (controller.onpositionstatechange = r)
+  );
+  MediaControlService.generateMediaControlKey("seekforward");
+  await positionChangePromise;
+  ok(true, "active media session received media key");
+}
+
+function removePlayingMedia(tab) {
+  return SpecialPowers.spawn(tab.linkedBrowser, [testVideoId], Id => {
+    content.document.getElementById(Id).remove();
+  });
+}
+
+async function checkOrWaitControllerBecomesActive(tab) {
+  const controller = tab.linkedBrowser.browsingContext.mediaController;
+  if (!controller.isActive) {
+    info(`wait until controller gets activated`);
+    await new Promise(r => (controller.onactivated = r));
+  }
+  ok(controller.isActive, `controller is active`);
+}