Bug 1676492, create a special blank tab page that will show the bookmarks toolbar when 'Only Show on New Tab' is used' even when the new tab page is disabled, r=Gijs,Mardak

Differential Revision: https://phabricator.services.mozilla.com/D154319
2022-11-01 20:43:01 +00:00 · 2022-11-01 20:43:01 +00:00 · e96d17d38c
--- a/browser/actors/AboutNewTabChild.sys.mjs
+++ b/browser/actors/AboutNewTabChild.sys.mjs
@ -24,6 +24,10 @@ XPCOMUtils.defineLazyPreferenceGetter(
 export class AboutNewTabChild extends JSWindowActorChild {
  handleEvent(event) {
    if (event.type == "DOMContentLoaded") {
+      if (!this.contentWindow.document.body.firstElementChild) {
+        return; // about:newtab is a blank page
+      }
+
      // If the separate about:welcome page is enabled, we can skip all of this,
      // since that mode doesn't load any of the Activity Stream bits.
      if (
--- a/browser/base/content/blanktab.html
+++ b/browser/base/content/blanktab.html
@ -0,0 +1,11 @@
+<!DOCTYPE html>
+
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<html>
+<head>
+  <meta http-equiv="Content-Security-Policy" content="default-src 'none'; style-src chrome:; object-src 'none'" >
+</head>
+</html>
--- a/browser/base/content/browser.js
+++ b/browser/base/content/browser.js
@ -663,6 +663,7 @@ var gInitialPages = [
  "about:sessionrestore",
  "about:welcome",
  "about:welcomeback",
+  "chrome://browser/content/blanktab.html",
 ];

 function isInitialPage(url) {
--- a/browser/base/content/test/about/browser_aboutNewTab_bookmarksToolbar.js
+++ b/browser/base/content/test/about/browser_aboutNewTab_bookmarksToolbar.js
@ -247,6 +247,10 @@ add_task(async function test_with_newtabpage_disabled() {
    visible: true,
    message: "Toolbar is visible with NTP enabled",
  });
+  let firstid = await SpecialPowers.spawn(newtab.linkedBrowser, [], () => {
+    return content.document.body.firstElementChild?.id;
+  });
+  is(firstid, "root", "new tab page contains content");
  await BrowserTestUtils.removeTab(newtab);

  await SpecialPowers.pushPrefEnv({
@ -256,11 +260,22 @@ add_task(async function test_with_newtabpage_disabled() {
  document.getElementById("cmd_newNavigatorTab").doCommand();
  await TestUtils.waitForCondition(() => gBrowser.tabs.length == tabCount + 1);
  newtab = gBrowser.selectedTab;
-  is(newtab.linkedBrowser.currentURI.spec, "about:blank", "blank is loaded");
+
  await waitForBookmarksToolbarVisibility({
-    visible: false,
-    message: "Toolbar is not visible with NTP disabled",
+    visible: true,
+    message: "Toolbar is visible with NTP disabled",
  });
+
+  is(
+    newtab.linkedBrowser.currentURI.spec,
+    "about:newtab",
+    "blank new tab is loaded"
+  );
+  firstid = await SpecialPowers.spawn(newtab.linkedBrowser, [], () => {
+    return content.document.body.firstElementChild;
+  });
+  ok(!firstid, "blank new tab page contains no content");
+
  await BrowserTestUtils.removeTab(newtab);

  await SpecialPowers.pushPrefEnv({
--- a/browser/base/jar.mn
+++ b/browser/base/jar.mn
@ -30,6 +30,7 @@ browser.jar:
        content/browser/aboutTabCrashed.css           (content/aboutTabCrashed.css)
        content/browser/aboutTabCrashed.js            (content/aboutTabCrashed.js)
        content/browser/aboutTabCrashed.xhtml         (content/aboutTabCrashed.xhtml)
+        content/browser/blanktab.html                 (content/blanktab.html)
        content/browser/browser.css                   (content/browser.css)
        content/browser/browser.js                    (content/browser.js)
 *       content/browser/browser.xhtml                 (content/browser.xhtml)
--- a/browser/components/about/AboutRedirector.cpp
+++ b/browser/components/about/AboutRedirector.cpp
@ -100,7 +100,7 @@ static const RedirEntry kRedirMap[] = {
    // Actual activity stream URL for home and newtab are set in channel
    // creation
    {"home", "about:blank", ACTIVITY_STREAM_FLAGS},
-    {"newtab", "about:blank", ACTIVITY_STREAM_FLAGS},
+    {"newtab", "chrome://browser/content/blanktab.html", ACTIVITY_STREAM_FLAGS},
    {"welcome", "about:blank",
     nsIAboutModule::URI_MUST_LOAD_IN_CHILD |
         nsIAboutModule::URI_CAN_LOAD_IN_PRIVILEGEDABOUT_PROCESS |
--- a/browser/components/newtab/test/browser/browser_enabled_newtabpage.js
+++ b/browser/components/newtab/test/browser/browser_enabled_newtabpage.js
@ -20,6 +20,14 @@ add_task(async function test_newtab_enabled() {
    set: [["browser.newtabpage.enabled", false]],
  });

-  checkSpec("about:newtab", is, "got blank when newtab is not enabled");
+  const { spec } = NetUtil.newChannel({
+    loadUsingSystemPrincipal: true,
+    uri: "about:newtab",
+  }).URI;
+
+  ok(
+    spec.endsWith("/blanktab.html"),
+    "got special blank page when newtab is not enabled"
+  );
  checkSpec("about:home", isnot, "still did not get blank for about:home");
 });