Bug 1847617 - Add about:home to the list of URLs we filter out when deciding if a closing window has state that should be saved. r=dao,sessionstore-reviewers

* And fix the urlbar test that breaks now that about:home tabs with no history aren't saved when closed.

Differential Revision: https://phabricator.services.mozilla.com/D185605

browser/components/sessionstore/SessionStore.sys.mjs

@@ -6149,6 +6149,7 @@ var SessionStoreInternal = {
       !(
         aTabState.entries.length == 1 &&
         (entryUrl == "about:blank" ||
+          entryUrl == "about:home" ||
           entryUrl == "about:newtab" ||
           entryUrl == "about:privatebrowsing") &&
         !aTabState.userTypedValue

browser/components/sessionstore/test/browser.ini

@@ -365,6 +365,7 @@ skip-if =
   os == "win" && os_version == "6.1" # Skip on Azure - frequent failure
 [browser_sessionStorage_size.js]
 [browser_sessionStoreContainer.js]
+[browser_should_restore_tab.js]
 [browser_sizemodeBeforeMinimized.js]
 [browser_speculative_connect.js]
 [browser_swapDocShells.js]

browser/components/sessionstore/test/browser_should_restore_tab.js

@@ -0,0 +1,139 @@
+const NOTIFY_CLOSED_OBJECTS_CHANGED = "sessionstore-closed-objects-changed";
+
+add_setup(async () => {
+  registerCleanupFunction(async () => {
+    Services.obs.notifyObservers(null, "browser:purge-session-history");
+  });
+});
+
+async function check_tab_close_notification(openedTab, expectNotification) {
+  let tabUrl = openedTab.linkedBrowser.currentURI.spec;
+  let win = openedTab.ownerGlobal;
+  let initialTabCount = SessionStore.getClosedTabCountForWindow(win);
+
+  let tabClosed = BrowserTestUtils.waitForTabClosing(openedTab);
+  let notified = false;
+  function topicObserver(_, topic) {
+    notified = true;
+  }
+  Services.obs.addObserver(topicObserver, NOTIFY_CLOSED_OBJECTS_CHANGED);
+
+  BrowserTestUtils.removeTab(openedTab);
+  await tabClosed;
+  // SessionStore does a setTimeout(notify, 0) to notifyObservers when it handles TabClose
+  // We need to wait long enough to be confident the observer would have been notified
+  // if it was going to be.
+  let ticks = 0;
+  await TestUtils.waitForCondition(() => {
+    return ++ticks > 1;
+  });
+
+  Services.obs.removeObserver(topicObserver, NOTIFY_CLOSED_OBJECTS_CHANGED);
+  if (expectNotification) {
+    Assert.ok(
+      notified,
+      `Expected ${NOTIFY_CLOSED_OBJECTS_CHANGED} when the ${tabUrl} tab closed`
+    );
+    Assert.equal(
+      SessionStore.getClosedTabCountForWindow(win),
+      initialTabCount + 1,
+      "Expected closed tab count to have incremented"
+    );
+  } else {
+    Assert.ok(
+      !notified,
+      `Expected no ${NOTIFY_CLOSED_OBJECTS_CHANGED} when the ${tabUrl} tab closed`
+    );
+    Assert.equal(
+      SessionStore.getClosedTabCountForWindow(win),
+      initialTabCount,
+      "Expected closed tab count to have not changed"
+    );
+  }
+}
+
+add_task(async function test_control_case() {
+  let win = window;
+  let tabOpenedAndSwitchedTo = BrowserTestUtils.switchTab(
+    win.gBrowser,
+    () => {}
+  );
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    win.gBrowser,
+    "https://example.com/"
+  );
+  await tabOpenedAndSwitchedTo;
+  await check_tab_close_notification(tab, true);
+});
+
+add_task(async function test_about_new_tab() {
+  let win = window;
+  let tabOpenedAndSwitchedTo = BrowserTestUtils.switchTab(
+    win.gBrowser,
+    () => {}
+  );
+  // This opens about:newtab:
+  win.BrowserOpenTab();
+  let tab = await tabOpenedAndSwitchedTo;
+  await check_tab_close_notification(tab, false);
+});
+
+add_task(async function test_about_home() {
+  let win = window;
+  let tabOpenedAndSwitchedTo = BrowserTestUtils.switchTab(
+    win.gBrowser,
+    () => {}
+  );
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    win.gBrowser,
+    "about:home"
+  );
+  await tabOpenedAndSwitchedTo;
+  await check_tab_close_notification(tab, false);
+});
+
+add_task(async function test_navigated_about_home() {
+  let win = window;
+  let tabOpenedAndSwitchedTo = BrowserTestUtils.switchTab(
+    win.gBrowser,
+    () => {}
+  );
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    win.gBrowser,
+    "https://example.com/"
+  );
+  await tabOpenedAndSwitchedTo;
+  BrowserTestUtils.loadURIString(tab.linkedBrowser, "about:home");
+  await BrowserTestUtils.browserLoaded(tab.linkedBrowser);
+  // even if we end up on an ignorable URL,
+  // if there's meaningful history, we should save this tab
+  await check_tab_close_notification(tab, true);
+});
+
+add_task(async function test_about_blank() {
+  let win = window;
+  let tabOpenedAndSwitchedTo = BrowserTestUtils.switchTab(
+    win.gBrowser,
+    () => {}
+  );
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    win.gBrowser,
+    "about:blank"
+  );
+  await tabOpenedAndSwitchedTo;
+  await check_tab_close_notification(tab, false);
+});
+
+add_task(async function test_about_privatebrowsing() {
+  let win = window;
+  let tabOpenedAndSwitchedTo = BrowserTestUtils.switchTab(
+    win.gBrowser,
+    () => {}
+  );
+  let tab = await BrowserTestUtils.openNewForegroundTab(
+    win.gBrowser,
+    "about:privatebrowsing"
+  );
+  await tabOpenedAndSwitchedTo;
+  await check_tab_close_notification(tab, false);
+});