Bug 1649532 - Add cross origin DecoderDoctor notification test. r=Gijs

Expand the decoder doctor browser chrome test to check that notifications
trigger the expected UI behaviour when sent from cross origin iframes.

Differential Revision: https://phabricator.services.mozilla.com/D88651

browser/base/content/test/general/browser_decoderDoctor.js

@@ -20,28 +20,61 @@ async function test_decoder_doctor_notification(
   accessKey,
   tabChecker
 ) {
-  if (typeof data.type === "undefined") {
-    ok(false, "Test implementation error: data.type must be provided");
-    return;
-  }
-  data.isSolved = data.isSolved || false;
-  if (typeof data.decoderDoctorReportId === "undefined") {
-    data.decoderDoctorReportId = "testReportId";
-  }
-  await BrowserTestUtils.withNewTab({ gBrowser }, async function(browser) {
+  const TEST_URL = "https://example.org";
+  // A helper closure to test notifications in same or different origins.
+  // 'test_cross_origin' is used to determine if the observers used in the test
+  // are notified in the same frame (when false) or in a cross origin iframe
+  // (when true).
+  async function create_tab_and_test(test_cross_origin) {
+    await BrowserTestUtils.withNewTab(
+      { gBrowser, url: TEST_URL },
+      async function(browser) {
         let awaitNotificationBar = BrowserTestUtils.waitForNotificationBar(
           gBrowser,
           browser,
           "decoder-doctor-notification"
         );
 
-    await SpecialPowers.spawn(browser, [data], async function(aData) {
+        await SpecialPowers.spawn(
+          browser,
+          [data, test_cross_origin],
+          /* eslint-disable-next-line no-shadow */
+          async function(data, test_cross_origin) {
+            if (!test_cross_origin) {
+              // Notify in the same origin.
               Services.obs.notifyObservers(
                 content.window,
                 "decoder-doctor-notification",
-        JSON.stringify(aData)
+                JSON.stringify(data)
+              );
+              return;
+              // Done notifying in the same origin.
+            }
+
+            // Notify in a different origin.
+            const CROSS_ORIGIN_URL = "https://example.com";
+            let frame = content.document.createElement("iframe");
+            frame.src = CROSS_ORIGIN_URL;
+            await new Promise(resolve => {
+              frame.addEventListener("load", () => {
+                resolve();
+              });
+              content.document.body.appendChild(frame);
+            });
+
+            await content.SpecialPowers.spawn(frame, [data], async function(
+              /* eslint-disable-next-line no-shadow */
+              data
+            ) {
+              Services.obs.notifyObservers(
+                content.window,
+                "decoder-doctor-notification",
+                JSON.stringify(data)
               );
             });
+            // Done notifying in a different origin.
+          }
+        );
 
         if (!notificationMessage) {
           ok(
@@ -92,7 +125,23 @@ async function test_decoder_doctor_notification(
         let openedTab = await awaitNewTab;
         tabChecker(openedTab);
         BrowserTestUtils.removeTab(openedTab);
-  });
+      }
+    );
+  }
+
+  if (typeof data.type === "undefined") {
+    ok(false, "Test implementation error: data.type must be provided");
+    return;
+  }
+  data.isSolved = data.isSolved || false;
+  if (typeof data.decoderDoctorReportId === "undefined") {
+    data.decoderDoctorReportId = "testReportId";
+  }
+
+  // Test same origin.
+  await create_tab_and_test(false);
+  // Test cross origin.
+  await create_tab_and_test(true);
 }
 
 function tab_checker_for_sumo(expectedPath) {