Bug 1643998: Check actual remote type along with PID when testing for privileged about: process. r=nika

We're getting some intermittent failures on automation where the PID does not
match the original privileged process in some checks. It isn't clear whether
that's because we're actually not in a privileged process, though, or whether
the original privileged process was simply replaced.

The new checks will tell us both things.

Differential Revision: https://phabricator.services.mozilla.com/D117361

browser/base/content/test/tabs/browser_new_tab_in_privilegedabout_process_pref.js

@@ -117,11 +117,29 @@ add_task(async function process_switching_through_loading_in_the_same_tab() {
 add_task(async function process_switching_through_navigation_features() {
   Services.ppmm.releaseCachedProcesses();
 
-  await BrowserTestUtils.withNewTab(ABOUT_NEWTAB, async function(browser) {
-    checkBrowserRemoteType(browser, E10SUtils.PRIVILEGEDABOUT_REMOTE_TYPE);
+  await BrowserTestUtils.withNewTab(ABOUT_NEWTAB, async function(
+    initialBrowser
+  ) {
+    checkBrowserRemoteType(
+      initialBrowser,
+      E10SUtils.PRIVILEGEDABOUT_REMOTE_TYPE
+    );
 
     // Note the processID for about:newtab for comparison later.
-    let privilegedPid = browser.frameLoader.remoteTab.osPid;
+    let privilegedPid = initialBrowser.frameLoader.remoteTab.osPid;
+
+    function assertIsPrivilegedProcess(browser, desc) {
+      is(
+        browser.messageManager.remoteType,
+        E10SUtils.PRIVILEGEDABOUT_REMOTE_TYPE,
+        `Check that ${desc} is loaded in privileged about: content process.`
+      );
+      is(
+        browser.frameLoader.remoteTab.osPid,
+        privilegedPid,
+        `Check that ${desc} is loaded in original privileged process.`
+      );
+    }
 
     // Check that about:newtab opened from JS in about:newtab page is in the same process.
     let promiseTabOpened = BrowserTestUtils.waitForNewTab(
@@ -129,28 +147,20 @@ add_task(async function process_switching_through_navigation_features() {
       ABOUT_NEWTAB,
       true
     );
-    await SpecialPowers.spawn(browser, [ABOUT_NEWTAB], uri => {
+    await SpecialPowers.spawn(initialBrowser, [ABOUT_NEWTAB], uri => {
       content.open(uri, "_blank");
     });
     let newTab = await promiseTabOpened;
     registerCleanupFunction(async function() {
       BrowserTestUtils.removeTab(newTab);
     });
-    browser = newTab.linkedBrowser;
-    is(
-      browser.frameLoader.remoteTab.osPid,
-      privilegedPid,
-      "Check that new tab opened from about:newtab is loaded in privileged about: content process."
-    );
+    let browser = newTab.linkedBrowser;
+    assertIsPrivilegedProcess(browser, "new tab opened from about:newtab");
 
     // Check that reload does not break the privileged about: content process affinity.
     BrowserReload();
     await BrowserTestUtils.browserLoaded(browser, false, ABOUT_NEWTAB);
-    is(
-      browser.frameLoader.remoteTab.osPid,
-      privilegedPid,
-      "Check that about:newtab is still in privileged about: content process after reload."
-    );
+    assertIsPrivilegedProcess(browser, "about:newtab after reload");
 
     // Load http webpage
     BrowserTestUtils.loadURI(browser, TEST_HTTP);
@@ -167,11 +177,7 @@ add_task(async function process_switching_through_navigation_features() {
     // We will need to ensure that the process flip has fully completed so that
     // the navigation history data will be available when we do browser.goForward();
     await BrowserTestUtils.browserLoaded(browser);
-    is(
-      browser.frameLoader.remoteTab.osPid,
-      privilegedPid,
-      "Check that about:newtab is still in privileged about: content process after history goBack."
-    );
+    assertIsPrivilegedProcess(browser, "about:newtab after history goBack");
 
     // Check that using the history forward feature switches back to the web content process.
     promiseLocation = BrowserTestUtils.waitForLocationChange(
@@ -201,6 +207,7 @@ add_task(async function process_switching_through_navigation_features() {
       privilegedPid,
       "Check that about:newtab is in privileged about: content process after history gotoIndex."
     );
+    assertIsPrivilegedProcess(browser, "about:newtab after history goToIndex");
 
     BrowserTestUtils.loadURI(browser, TEST_HTTP);
     await BrowserTestUtils.browserLoaded(browser, false, TEST_HTTP);
@@ -211,11 +218,7 @@ add_task(async function process_switching_through_navigation_features() {
       content.location = uri;
     });
     await BrowserTestUtils.browserLoaded(browser, false, ABOUT_NEWTAB);
-    is(
-      browser.frameLoader.remoteTab.osPid,
-      privilegedPid,
-      "Check that about:newtab is in privileged about: content process after location change."
-    );
+    assertIsPrivilegedProcess(browser, "about:newtab after location change");
   });
 
   Services.ppmm.releaseCachedProcesses();