Bug 1733902 - part4 : add a test. r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D128165

toolkit/content/tests/browser/browser.ini

@@ -6,6 +6,7 @@ support-files =
   empty.png
   file_contentTitle.html
   file_empty.html
+  file_iframe_media.html
   file_findinframe.html
   file_mediaPlayback2.html
   file_multipleAudio.html
@@ -15,6 +16,7 @@ support-files =
   file_redirect_to.html
   file_silentAudioTrack.html
   file_webAudio.html
+  gizmo.mp4
   head.js
   image.jpg
   image_page.html
@@ -24,6 +26,8 @@ support-files =
 skip-if = true # Bug 1312652
 [browser_autoscroll_disabled_on_editable_content.js]
 [browser_autoscroll_disabled_on_links.js]
+[browser_delay_autoplay_cross_origin_iframe.js]
+tags = audiochannel
 [browser_delay_autoplay_media.js]
 tags = audiochannel
 skip-if =
@@ -130,7 +134,7 @@ skip-if = e10s # Bug ?????? - test directly manipulates content (gBrowser.conten
 [browser_saveImageURL.js]
 [browser_starting_autoscroll_in_about_content.js]
 [browser_resume_bkg_video_on_tab_hover.js]
-skip-if = 
+skip-if =
   os == "win" && processor == "aarch64"  # Bug 1536573
   debug  # Bug 1388959
 [browser_about_networking.js]

toolkit/content/tests/browser/browser_delay_autoplay_cross_origin_iframe.js

@@ -0,0 +1,99 @@
+/**
+ * After the tab has been visited, all media should be able to start playing.
+ * This test is used to ensure that playing media from a cross-origin iframe in
+ * a tab that has been already visited won't fail.
+ */
+"use strict";
+
+add_task(async function setupTestEnvironment() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["media.autoplay.default", 0],
+      ["media.block-autoplay-until-in-foreground", true],
+    ],
+  });
+});
+
+add_task(async function testCrossOriginIframeShouldBeAbleToStart() {
+  info("Create a new foreground tab");
+  const originalTab = gBrowser.selectedTab;
+  const tab = await BrowserTestUtils.openNewForegroundTab(
+    window.gBrowser,
+    "about:blank"
+  );
+
+  info("As tab has been visited, media should be allowed to start");
+  const MEDIA_FILE = "gizmo.mp4";
+  await SpecialPowers.spawn(
+    tab.linkedBrowser,
+    [getTestWebBasedURL(MEDIA_FILE)],
+    async url => {
+      let vid = content.document.createElement("video");
+      vid.src = url;
+      ok(
+        await vid.play().then(
+          _ => true,
+          _ => false
+        ),
+        "video started playing"
+      );
+    }
+  );
+
+  info("Make the tab to background");
+  await BrowserTestUtils.switchTab(gBrowser, originalTab);
+
+  info(
+    "As tab has been visited, a cross-origin iframe should be able to start media"
+  );
+  const IFRAME_FILE = "file_iframe_media.html";
+  await createIframe(
+    tab.linkedBrowser,
+    getTestWebBasedURL(IFRAME_FILE, { crossOrigin: true })
+  );
+  await ensureCORSIframeCanStartPlayingMedia(tab.linkedBrowser);
+
+  info("Remove tab");
+  BrowserTestUtils.removeTab(tab);
+});
+
+/**
+ * Following are helper functions
+ */
+function getTestWebBasedURL(fileName, { crossOrigin = false } = {}) {
+  const origin = crossOrigin ? "http://example.org" : "http://example.com";
+  return (
+    getRootDirectory(gTestPath).replace("chrome://mochitests/content", origin) +
+    fileName
+  );
+}
+
+function createIframe(browser, iframeUrl) {
+  return SpecialPowers.spawn(browser, [iframeUrl], async url => {
+    info(`Create iframe and wait until it finishes loading`);
+    const iframe = content.document.createElement("iframe");
+    const iframeLoaded = new Promise(r => (iframe.onload = r));
+    iframe.src = url;
+    content.document.body.appendChild(iframe);
+    await iframeLoaded;
+  });
+}
+
+function ensureCORSIframeCanStartPlayingMedia(browser) {
+  return SpecialPowers.spawn(browser, [], async _ => {
+    info(`check if media in iframe can start playing`);
+    const iframe = content.document.querySelector("iframe");
+    if (!iframe) {
+      ok(false, `can not get the iframe!`);
+      return;
+    }
+    const playPromise = new Promise(r => {
+      content.onmessage = event => {
+        is(event.data, "played", `started playing media from CORS iframe`);
+        r();
+      };
+    });
+    iframe.contentWindow.postMessage("play", "*");
+    await playPromise;
+  });
+}

toolkit/content/tests/browser/file_iframe_media.html

@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<video id="video" src="gizmo.mp4" loop></video>
+<script type="text/javascript">
+
+window.onmessage = async event => {
+  const video = document.getElementById("video");
+  const w = window.opener || window.parent;
+  if (event.data == "play") {
+    await video.play();
+    w.postMessage("played", "*");
+  }
+}
+
+</script>