From f9c236531f0614b54c3bf386662b997e519d4582 Mon Sep 17 00:00:00 2001
From: Mark Banner <standard8@mozilla.com>
Date: Mon, 30 Sep 2019 19:18:26 +0000
Subject: [PATCH] Bug 1563021 - Add preferences UI to allow enabling and
 selection of a separate default private engine. r=fluent-reviewers,jaws,flod

Differential Revision: https://phabricator.services.mozilla.com/D46971

--HG--
extra : moz-landing-system : lando
---
 browser/app/profile/firefox.js                |   4 +
 .../preferences/in-content/privacy.inc.xul    |   3 +-
 .../preferences/in-content/search.inc.xul     |  21 ++
 .../preferences/in-content/search.js          | 145 ++++++++-
 .../preferences/in-content/tests/browser.ini  |   4 +
 .../tests/browser_searchDefaultEngine.js      | 277 ++++++++++++++++++
 .../in-content/tests/engine1/manifest.json    |  27 ++
 .../in-content/tests/engine2/manifest.json    |  27 ++
 .../en-US/browser/preferences/preferences.ftl |   9 +
 .../shared/incontentprefs/preferences.inc.css |   2 +-
 .../themes/shared/incontentprefs/search.css   |   6 +-
 11 files changed, 505 insertions(+), 20 deletions(-)
 create mode 100644 browser/components/preferences/in-content/tests/browser_searchDefaultEngine.js
 create mode 100644 browser/components/preferences/in-content/tests/engine1/manifest.json
 create mode 100644 browser/components/preferences/in-content/tests/engine2/manifest.json

diff --git a/browser/app/profile/firefox.js b/browser/app/profile/firefox.js
index ea6155a1d854..e7bfaf43d1d3 100644
--- a/browser/app/profile/firefox.js
+++ b/browser/app/profile/firefox.js
@@ -386,6 +386,10 @@ pref("browser.search.hiddenOneOffs", "");
 // Mirrors whether the search-container widget is in the navigation toolbar.
 pref("browser.search.widget.inNavBar", false);
 
+// Enables display of the options for the user using a separate default search
+// engine in private browsing mode.
+pref("browser.search.separatePrivateDefault.ui.enabled", false);
+
 pref("browser.sessionhistory.max_entries", 50);
 
 // Built-in default permissions.
diff --git a/browser/components/preferences/in-content/privacy.inc.xul b/browser/components/preferences/in-content/privacy.inc.xul
index f2d59cae1efa..6c3cf966df74 100644
--- a/browser/components/preferences/in-content/privacy.inc.xul
+++ b/browser/components/preferences/in-content/privacy.inc.xul
@@ -621,7 +621,8 @@
 <!-- Address Bar -->
 <groupbox id="locationBarGroup"
           data-category="panePrivacy"
-          hidden="true">
+          hidden="true"
+          data-subcategory="locationBar">
   <label><html:h2 data-l10n-id="addressbar-header"/></label>
   <label id="locationBarSuggestionLabel" data-l10n-id="addressbar-suggest"/>
   <checkbox id="historySuggestion" data-l10n-id="addressbar-locbar-history-option"
diff --git a/browser/components/preferences/in-content/search.inc.xul b/browser/components/preferences/in-content/search.inc.xul
index 75adc1c86e56..05d6efb8c893 100644
--- a/browser/components/preferences/in-content/search.inc.xul
+++ b/browser/components/preferences/in-content/search.inc.xul
@@ -39,6 +39,25 @@
           </menulist>
         </hbox>
       </hbox>
+      <checkbox id="browserSeparateDefaultEngine"
+                data-l10n-id="search-separate-default-engine"
+                hidden="true"/>
+      <vbox id="browserPrivateEngineSelection" class="indent" hidden="true">
+        <description data-l10n-id="search-engine-default-private-desc" />
+        <hbox>
+          <!-- Please don't remove the wrapping hbox/vbox/box for these elements. It's used to properly compute the search tooltip position. -->
+          <hbox>
+            <menulist id="defaultPrivateEngine">
+              <menupopup/>
+            </menulist>
+          </hbox>
+        </hbox>
+      </vbox>
+    </groupbox>
+
+    <groupbox id="searchSuggestionsGroup" data-category="paneSearch" hidden="true">
+      <label><html:h2 data-l10n-id="search-suggestions-header" /></label>
+      <description data-l10n-id="search-suggestions-desc" />
 
       <checkbox id="suggestionsInSearchFieldsCheckbox"
                 data-l10n-id="search-suggestions-option"
@@ -52,6 +71,8 @@
           <label flex="1" data-l10n-id="search-suggestions-cant-show" />
         </hbox>
       </vbox>
+      <label id="openLocationBarPrivacyPreferences" is="text-link"
+             data-l10n-id="suggestions-addressbar-settings"/>
     </groupbox>
 
     <groupbox id="oneClickSearchProvidersGroup" data-category="paneSearch" hidden="true">
diff --git a/browser/components/preferences/in-content/search.js b/browser/components/preferences/in-content/search.js
index aecbf7ddb681..748d16d8b344 100644
--- a/browser/components/preferences/in-content/search.js
+++ b/browser/components/preferences/in-content/search.js
@@ -22,6 +22,8 @@ Preferences.addAll([
   { id: "browser.search.hiddenOneOffs", type: "unichar" },
   { id: "browser.search.widget.inNavBar", type: "bool" },
   { id: "browser.urlbar.matchBuckets", type: "string" },
+  { id: "browser.search.separatePrivateDefault", type: "bool" },
+  { id: "browser.search.separatePrivateDefault.ui.enabled", type: "bool" },
 ]);
 
 const ENGINE_FLAVOR = "text/x-moz-search-engine";
@@ -43,7 +45,7 @@ var gSearchPane = {
   init() {
     gEngineView = new EngineView(new EngineStore());
     document.getElementById("engineList").view = gEngineView;
-    this.buildDefaultEngineDropDown();
+    this.buildDefaultEngineDropDowns().catch(console.error);
 
     if (
       Services.policies &&
@@ -84,10 +86,67 @@ var gSearchPane = {
       urlbarSuggestsPref.value = urlbarSuggests.checked;
     });
 
+    setEventListener(
+      "browserSeparateDefaultEngine",
+      "command",
+      this._onBrowserSeparateDefaultEngineChange.bind(this)
+    );
+    setEventListener("openLocationBarPrivacyPreferences", "click", function(
+      event
+    ) {
+      if (event.button == 0) {
+        gotoPref("privacy-locationBar");
+      }
+    });
+
+    this._initDefaultEngines();
     this._initShowSearchSuggestionsFirst();
     this._updateSuggestionCheckboxes();
   },
 
+  /**
+   * Initialize the default engine handling. This will hide the private default
+   * options if they are not enabled yet.
+   */
+  _initDefaultEngines() {
+    this._separatePrivateDefaultEnabledPref = Preferences.get(
+      "browser.search.separatePrivateDefault.ui.enabled"
+    );
+
+    this._separatePrivateDefaultPref = Preferences.get(
+      "browser.search.separatePrivateDefault"
+    );
+
+    const checkbox = document.getElementById("browserSeparateDefaultEngine");
+    checkbox.checked = !this._separatePrivateDefaultPref.value;
+
+    this._updatePrivateEngineDisplayBoxes();
+
+    const listener = () => {
+      this._updatePrivateEngineDisplayBoxes();
+      this.buildDefaultEngineDropDowns().catch(console.error);
+    };
+
+    this._separatePrivateDefaultEnabledPref.on("change", listener);
+    this._separatePrivateDefaultPref.on("change", listener);
+  },
+
+  _updatePrivateEngineDisplayBoxes() {
+    const separateEnabled = this._separatePrivateDefaultEnabledPref.value;
+    document.getElementById(
+      "browserSeparateDefaultEngine"
+    ).hidden = !separateEnabled;
+
+    const separateDefault = this._separatePrivateDefaultPref.value;
+
+    const vbox = document.getElementById("browserPrivateEngineSelection");
+    vbox.hidden = !separateEnabled || !separateDefault;
+  },
+
+  _onBrowserSeparateDefaultEngineChange(event) {
+    this._separatePrivateDefaultPref.value = !event.target.checked;
+  },
+
   _initShowSearchSuggestionsFirst() {
     this._urlbarSuggestionsPosPref = Preferences.get(
       "browser.urlbar.matchBuckets"
@@ -163,12 +222,37 @@ var gSearchPane = {
     permanentPBLabel.hidden = urlbarSuggests.hidden || !permanentPB;
   },
 
-  async buildDefaultEngineDropDown() {
-    // This is called each time something affects the list of engines.
-    let list = document.getElementById("defaultEngine");
-    // Set selection to the current default engine.
-    let currentEngine = (await Services.search.getDefault()).name;
+  /**
+   * Builds the default and private engines drop down lists. This is called
+   * each time something affects the list of engines.
+   */
+  async buildDefaultEngineDropDowns() {
+    await this._buildEngineDropDown(
+      document.getElementById("defaultEngine"),
+      (await Services.search.getDefault()).name,
+      false
+    );
 
+    if (this._separatePrivateDefaultEnabledPref.value) {
+      await this._buildEngineDropDown(
+        document.getElementById("defaultPrivateEngine"),
+        (await Services.search.getDefaultPrivate()).name,
+        true
+      );
+    }
+  },
+
+  /**
+   * Builds a drop down menu of search engines.
+   *
+   * @param {DOMMenuList} list
+   *   The menu list element to attach the list of engines.
+   * @param {string} currentEngine
+   *   The name of the current default engine.
+   * @param {boolean} isPrivate
+   *   True if we are dealing with the default engine for private mode.
+   */
+  async _buildEngineDropDown(list, currentEngine, isPrivate) {
     // If the current engine isn't in the list any more, select the first item.
     let engines = gEngineView._engineStore._engines;
     if (!engines.length) {
@@ -195,6 +279,12 @@ var gSearchPane = {
       }
     });
 
+    // We don't currently support overriding the engine for private mode with
+    // extensions.
+    if (isPrivate) {
+      return;
+    }
+
     handleControllingExtension(SEARCH_TYPE, SEARCH_KEY);
     let searchEngineListener = {
       observe(subject, topic, data) {
@@ -241,10 +331,15 @@ var gSearchPane = {
           case "":
             if (
               aEvent.target.parentNode &&
-              aEvent.target.parentNode.parentNode &&
-              aEvent.target.parentNode.parentNode.id == "defaultEngine"
+              aEvent.target.parentNode.parentNode
             ) {
-              gSearchPane.setDefaultEngine();
+              if (aEvent.target.parentNode.parentNode.id == "defaultEngine") {
+                gSearchPane.setDefaultEngine();
+              } else if (
+                aEvent.target.parentNode.parentNode.id == "defaultPrivateEngine"
+              ) {
+                gSearchPane.setDefaultPrivateEngine();
+              }
             }
             break;
           case "restoreDefaultSearchEngines":
@@ -291,7 +386,7 @@ var gSearchPane = {
         case "engine-added":
           gEngineView._engineStore.addEngine(aEngine);
           gEngineView.rowCountChanged(gEngineView.lastIndex, 1);
-          gSearchPane.buildDefaultEngineDropDown();
+          gSearchPane.buildDefaultEngineDropDowns();
           break;
         case "engine-changed":
           gEngineView._engineStore.reloadIcons();
@@ -300,16 +395,28 @@ var gSearchPane = {
         case "engine-removed":
           gSearchPane.remove(aEngine);
           break;
-        case "engine-default":
+        case "engine-default": {
           // If the user is going through the drop down using up/down keys, the
           // dropdown may still be open (eg. on Windows) when engine-default is
           // fired, so rebuilding the list unconditionally would get in the way.
           let selectedEngine = document.getElementById("defaultEngine")
             .selectedItem.engine;
           if (selectedEngine.name != aEngine.name) {
-            gSearchPane.buildDefaultEngineDropDown();
+            gSearchPane.buildDefaultEngineDropDowns();
           }
           break;
+        }
+        case "engine-default-private": {
+          // If the user is going through the drop down using up/down keys, the
+          // dropdown may still be open (eg. on Windows) when engine-default is
+          // fired, so rebuilding the list unconditionally would get in the way.
+          const selectedEngine = document.getElementById("defaultPrivateEngine")
+            .selectedItem.engine;
+          if (selectedEngine.name != aEngine.name) {
+            gSearchPane.buildDefaultEngineDropDowns();
+          }
+          break;
+        }
       }
     }
   },
@@ -453,6 +560,12 @@ var gSearchPane = {
     );
     ExtensionSettingsStore.setByUser(SEARCH_TYPE, SEARCH_KEY);
   },
+
+  async setDefaultPrivateEngine() {
+    await Services.search.setDefaultPrivate(
+      document.getElementById("defaultPrivateEngine").selectedItem.engine
+    );
+  },
 };
 
 function onDragEngineStart(event) {
@@ -480,7 +593,7 @@ function EngineStore() {
       gEngineView.rowCountChanged(gEngineView.lastIndex, 1);
     }
     this._defaultEngines = defaultEngines.map(this._cloneEngine, this);
-    gSearchPane.buildDefaultEngineDropDown();
+    gSearchPane.buildDefaultEngineDropDowns();
 
     // check if we need to disable the restore defaults button
     var someHidden = this._defaultEngines.some(e => e.hidden);
@@ -563,7 +676,7 @@ EngineStore.prototype = {
     if (this._defaultEngines.some(this._isSameEngine, removedEngine)) {
       gSearchPane.showRestoreDefaults(true);
     }
-    gSearchPane.buildDefaultEngineDropDown();
+    gSearchPane.buildDefaultEngineDropDowns();
     return index;
   },
 
@@ -592,7 +705,7 @@ EngineStore.prototype = {
     }
     Services.search.resetToOriginalDefaultEngine();
     gSearchPane.showRestoreDefaults(false);
-    gSearchPane.buildDefaultEngineDropDown();
+    gSearchPane.buildDefaultEngineDropDowns();
     return added;
   },
 
@@ -720,7 +833,7 @@ EngineView.prototype = {
 
     await this._engineStore.moveEngine(sourceEngine, dropIndex);
     gSearchPane.showRestoreDefaults(true);
-    gSearchPane.buildDefaultEngineDropDown();
+    gSearchPane.buildDefaultEngineDropDowns();
 
     // Redraw, and adjust selection
     this.invalidate();
diff --git a/browser/components/preferences/in-content/tests/browser.ini b/browser/components/preferences/in-content/tests/browser.ini
index e3f4562f5cb9..f705f62ca313 100644
--- a/browser/components/preferences/in-content/tests/browser.ini
+++ b/browser/components/preferences/in-content/tests/browser.ini
@@ -81,6 +81,10 @@ skip-if = e10s
 [browser_privacypane_3.js]
 [browser_privacy_passwordGenerationAndAutofill.js]
 [browser_sanitizeOnShutdown_prefLocked.js]
+[browser_searchDefaultEngine.js]
+support-files =
+  engine1/manifest.json
+  engine2/manifest.json
 [browser_searchShowSuggestionsFirst.js]
 [browser_searchsuggestions.js]
 [browser_security-1.js]
diff --git a/browser/components/preferences/in-content/tests/browser_searchDefaultEngine.js b/browser/components/preferences/in-content/tests/browser_searchDefaultEngine.js
new file mode 100644
index 000000000000..45834c80b7d2
--- /dev/null
+++ b/browser/components/preferences/in-content/tests/browser_searchDefaultEngine.js
@@ -0,0 +1,277 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const { SearchTestUtils } = ChromeUtils.import(
+  "resource://testing-common/SearchTestUtils.jsm"
+);
+
+add_task(async function setup() {
+  const engine1 = await Services.search.addEngineWithDetails("engine1", {
+    method: "get",
+    template: "http://example.com/engine1?search={searchTerms}",
+  });
+
+  const engine2 = await Services.search.addEngineWithDetails("engine2", {
+    method: "get",
+    template: "http://example.com/engine2?search={searchTerms}",
+  });
+
+  const originalDefault = await Services.search.getDefault();
+  const originalDefaultPrivate = await Services.search.getDefaultPrivate();
+
+  registerCleanupFunction(async () => {
+    await Services.search.setDefault(originalDefault);
+    await Services.search.setDefaultPrivate(originalDefaultPrivate);
+
+    await Services.search.removeEngine(engine1);
+    await Services.search.removeEngine(engine2);
+  });
+});
+
+add_task(async function test_openWithPrivateDefaultNotEnabledFirst() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.search.separatePrivateDefault.ui.enabled", false],
+      ["browser.search.separatePrivateDefault", false],
+    ],
+  });
+
+  await openPreferencesViaOpenPreferencesAPI("search", { leaveOpen: true });
+
+  const doc = gBrowser.selectedBrowser.contentDocument;
+  const separateEngineCheckbox = doc.getElementById(
+    "browserSeparateDefaultEngine"
+  );
+  const privateDefaultVbox = doc.getElementById(
+    "browserPrivateEngineSelection"
+  );
+
+  Assert.ok(
+    separateEngineCheckbox.hidden,
+    "Should have hidden the separate search engine checkbox"
+  );
+  Assert.ok(
+    privateDefaultVbox.hidden,
+    "Should have hidden the private engine selection box"
+  );
+
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.search.separatePrivateDefault.ui.enabled", true]],
+  });
+
+  Assert.ok(
+    !separateEngineCheckbox.hidden,
+    "Should have displayed the separate search engine checkbox"
+  );
+  Assert.ok(
+    privateDefaultVbox.hidden,
+    "Should not have displayed the private engine selection box"
+  );
+
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.search.separatePrivateDefault", true]],
+  });
+
+  Assert.ok(
+    !separateEngineCheckbox.hidden,
+    "Should still be displaying the separate search engine checkbox"
+  );
+  Assert.ok(
+    !privateDefaultVbox.hidden,
+    "Should have displayed the private engine selection box"
+  );
+
+  gBrowser.removeCurrentTab();
+});
+
+add_task(async function test_openWithPrivateDefaultEnabledFirst() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.search.separatePrivateDefault.ui.enabled", true],
+      ["browser.search.separatePrivateDefault", true],
+    ],
+  });
+
+  await openPreferencesViaOpenPreferencesAPI("search", { leaveOpen: true });
+
+  const doc = gBrowser.selectedBrowser.contentDocument;
+  const separateEngineCheckbox = doc.getElementById(
+    "browserSeparateDefaultEngine"
+  );
+  const privateDefaultVbox = doc.getElementById(
+    "browserPrivateEngineSelection"
+  );
+
+  Assert.ok(
+    !separateEngineCheckbox.hidden,
+    "Should not have hidden the separate search engine checkbox"
+  );
+  Assert.ok(
+    !privateDefaultVbox.hidden,
+    "Should not have hidden the private engine selection box"
+  );
+
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.search.separatePrivateDefault", false]],
+  });
+
+  Assert.ok(
+    !separateEngineCheckbox.hidden,
+    "Should not have hidden the separate search engine checkbox"
+  );
+  Assert.ok(
+    privateDefaultVbox.hidden,
+    "Should have hidden the private engine selection box"
+  );
+
+  await SpecialPowers.pushPrefEnv({
+    set: [["browser.search.separatePrivateDefault.ui.enabled", false]],
+  });
+
+  Assert.ok(
+    separateEngineCheckbox.hidden,
+    "Should have hidden the separate private engine checkbox"
+  );
+  Assert.ok(
+    privateDefaultVbox.hidden,
+    "Should still be hiding the private engine selection box"
+  );
+
+  gBrowser.removeCurrentTab();
+});
+
+add_task(async function test_separatePrivateDefault() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.search.separatePrivateDefault.ui.enabled", true],
+      ["browser.search.separatePrivateDefault", false],
+    ],
+  });
+
+  await openPreferencesViaOpenPreferencesAPI("search", { leaveOpen: true });
+
+  const doc = gBrowser.selectedBrowser.contentDocument;
+  const separateEngineCheckbox = doc.getElementById(
+    "browserSeparateDefaultEngine"
+  );
+  const privateDefaultVbox = doc.getElementById(
+    "browserPrivateEngineSelection"
+  );
+
+  Assert.ok(
+    privateDefaultVbox.hidden,
+    "Should not be displaying the private engine selection box"
+  );
+
+  separateEngineCheckbox.checked = false;
+  separateEngineCheckbox.doCommand();
+
+  Assert.ok(
+    Services.prefs.getBoolPref("browser.search.separatePrivateDefault"),
+    "Should have correctly set the pref"
+  );
+
+  Assert.ok(
+    !privateDefaultVbox.hidden,
+    "Should be displaying the private engine selection box"
+  );
+
+  separateEngineCheckbox.checked = true;
+  separateEngineCheckbox.doCommand();
+
+  Assert.ok(
+    !Services.prefs.getBoolPref("browser.search.separatePrivateDefault"),
+    "Should have correctly turned the pref off"
+  );
+
+  Assert.ok(
+    privateDefaultVbox.hidden,
+    "Should have hidden the private engine selection box"
+  );
+
+  gBrowser.removeCurrentTab();
+});
+
+async function setDefaultEngine(
+  testPrivate,
+  currentEngineName,
+  expectedEngineName
+) {
+  await openPreferencesViaOpenPreferencesAPI("search", { leaveOpen: true });
+
+  const doc = gBrowser.selectedBrowser.contentDocument;
+  const defaultEngineSelector = doc.getElementById(
+    testPrivate ? "defaultPrivateEngine" : "defaultEngine"
+  );
+
+  Assert.equal(
+    defaultEngineSelector.selectedItem.engine.name,
+    currentEngineName,
+    "Should have the correct engine as default on first open"
+  );
+
+  const popup = defaultEngineSelector.menupopup;
+  const popupShown = BrowserTestUtils.waitForEvent(popup, "popupshown");
+  BrowserTestUtils.synthesizeMouseAtCenter(
+    defaultEngineSelector,
+    {},
+    gBrowser.selectedBrowser
+  );
+  await popupShown;
+
+  const items = Array.from(popup.children);
+  const engine2Item = items.find(
+    item => item.engine.name == expectedEngineName
+  );
+
+  const defaultChanged = SearchTestUtils.promiseSearchNotification(
+    testPrivate ? "engine-default-private" : "engine-default",
+    "browser-search-engine-modified"
+  );
+  const popupHidden = BrowserTestUtils.waitForEvent(popup, "popuphidden");
+  BrowserTestUtils.synthesizeMouseAtCenter(
+    engine2Item,
+    {},
+    gBrowser.selectedBrowser
+  );
+  await popupHidden;
+  await defaultChanged;
+
+  const newDefault = testPrivate
+    ? await Services.search.getDefaultPrivate()
+    : await Services.search.getDefault();
+  Assert.equal(
+    newDefault.name,
+    expectedEngineName,
+    "Should have changed the default engine to engine2"
+  );
+}
+
+add_task(async function test_setDefaultEngine() {
+  const engine1 = Services.search.getEngineByName("engine1");
+
+  // Set an initial default so we have a known engine.
+  await Services.search.setDefault(engine1);
+
+  await setDefaultEngine(false, "engine1", "engine2");
+
+  gBrowser.removeCurrentTab();
+});
+
+add_task(async function test_setPrivateDefaultEngine() {
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["browser.search.separatePrivateDefault.ui.enabled", true],
+      ["browser.search.separatePrivateDefault", true],
+    ],
+  });
+
+  const engine2 = Services.search.getEngineByName("engine2");
+
+  // Set an initial default so we have a known engine.
+  await Services.search.setDefaultPrivate(engine2);
+
+  await setDefaultEngine(true, "engine2", "engine1");
+
+  gBrowser.removeCurrentTab();
+});
diff --git a/browser/components/preferences/in-content/tests/engine1/manifest.json b/browser/components/preferences/in-content/tests/engine1/manifest.json
new file mode 100644
index 000000000000..e30a128de118
--- /dev/null
+++ b/browser/components/preferences/in-content/tests/engine1/manifest.json
@@ -0,0 +1,27 @@
+{
+  "name": "engine1",
+  "manifest_version": 2,
+  "version": "1.0",
+  "applications": {
+    "gecko": {
+      "id": "engine1@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "A small test engine",
+  "icons": {
+    "16": "favicon.ico"
+  },
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "engine1",
+      "search_url": "https://1.example.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        }
+      ]
+    }
+  }
+}
diff --git a/browser/components/preferences/in-content/tests/engine2/manifest.json b/browser/components/preferences/in-content/tests/engine2/manifest.json
new file mode 100644
index 000000000000..c69472ffcb50
--- /dev/null
+++ b/browser/components/preferences/in-content/tests/engine2/manifest.json
@@ -0,0 +1,27 @@
+{
+  "name": "engine2",
+  "manifest_version": 2,
+  "version": "1.0",
+  "applications": {
+    "gecko": {
+      "id": "engine2@search.mozilla.org"
+    }
+  },
+  "hidden": true,
+  "description": "A small test engine",
+  "icons": {
+    "16": "favicon.ico"
+  },
+  "chrome_settings_overrides": {
+    "search_provider": {
+      "name": "engine2",
+      "search_url": "https://2.example.com/search",
+      "params": [
+        {
+          "name": "q",
+          "value": "{searchTerms}"
+        }
+      ]
+    }
+  }
+}
diff --git a/browser/locales/en-US/browser/preferences/preferences.ftl b/browser/locales/en-US/browser/preferences/preferences.ftl
index 5bf3e366773d..c8587d56f7d8 100644
--- a/browser/locales/en-US/browser/preferences/preferences.ftl
+++ b/browser/locales/en-US/browser/preferences/preferences.ftl
@@ -629,6 +629,13 @@ search-bar-shown =
 
 search-engine-default-header = Default Search Engine
 search-engine-default-desc = Choose the default search engine to use in the address bar and search bar.
+search-engine-default-private-desc = Choose the default search engine to use in Private Windows.
+search-separate-default-engine =
+    .label = Use this search engine in Private Windows
+    .accesskey = U
+
+search-suggestions-header = Search Suggestions
+search-suggestions-desc = Choose how suggestions from search engines appear.
 
 search-suggestions-option =
     .label = Provide search suggestions
@@ -646,6 +653,8 @@ search-show-suggestions-url-bar-option =
 search-show-suggestions-above-history-option =
     .label = Show search suggestions ahead of browsing history in address bar results
 
+suggestions-addressbar-settings = Change preferences for browsing history, bookmarks, and tab suggestions
+
 search-suggestions-cant-show = Search suggestions will not be shown in location bar results because you have configured { -brand-short-name } to never remember history.
 
 search-one-click-header = One-Click Search Engines
diff --git a/browser/themes/shared/incontentprefs/preferences.inc.css b/browser/themes/shared/incontentprefs/preferences.inc.css
index d93321143571..98d21153f6db 100644
--- a/browser/themes/shared/incontentprefs/preferences.inc.css
+++ b/browser/themes/shared/incontentprefs/preferences.inc.css
@@ -54,7 +54,7 @@ html|h2 {
 }
 
 description.indent,
-.indent > description {
+.indent:not(#browserPrivateEngineSelection) > description {
   color: var(--in-content-deemphasized-text);
 }
 
diff --git a/browser/themes/shared/incontentprefs/search.css b/browser/themes/shared/incontentprefs/search.css
index 65d70fc7c285..89d5bdce6add 100644
--- a/browser/themes/shared/incontentprefs/search.css
+++ b/browser/themes/shared/incontentprefs/search.css
@@ -28,11 +28,13 @@
   transform: scaleX(-1);
 }
 
-#defaultEngine {
+#defaultEngine,
+#defaultPrivateEngine {
  margin-inline-start: 0;
 }
 
-#defaultEngine > .menulist-label-box > .menulist-icon {
+#defaultEngine > .menulist-label-box > .menulist-icon,
+#defaultPrivateEngine > .menulist-label-box > .menulist-icon {
   height: 16px;
 }