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diff --git a/browser/components/urlbar/private/BaseFeature.sys.mjs b/browser/components/urlbar/private/BaseFeature.sys.mjs
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+++ b/browser/components/urlbar/private/BaseFeature.sys.mjs
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+/* 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/. */
+
+const lazy = {};
+
+ChromeUtils.defineESModuleGetters(lazy, {
+  UrlbarPrefs: "resource:///modules/UrlbarPrefs.sys.mjs",
+  UrlbarUtils: "resource:///modules/UrlbarUtils.sys.mjs",
+});
+
+/**
+ * Base class for quick suggest features. It can be extended to implement a
+ * feature that is part of the larger quick suggest feature and that should be
+ * enabled only when quick suggest is enabled.
+ *
+ * You can extend this class as an alternative to implementing your feature
+ * directly in `QuickSuggest`. Doing so has the following advantages:
+ *
+ * - If your feature is gated on a Nimbus variable or preference, `QuickSuggest`
+ *   will manage its lifetime automatically. This is really only useful if the
+ *   feature has state that must be initialized when the feature is enabled and
+ *   uninitialized when it's disabled.
+ *
+ * - Encapsulation. You can keep all the code related to your feature in one
+ *   place, without mixing it with unrelated code and cluttering up
+ *   `QuickSuggest`. You can also test it in isolation from `QuickSuggest`.
+ *
+ * - Remote settings management. You can register your feature with
+ *   `QuickSuggestRemoteSettings` and it will be called at appropriate times to
+ *   sync from remote settings.
+ *
+ * - If your feature also serves suggestions from remote settings, you can
+ *   implement one method, `queryRemoteSettings()`, to hook into
+ *   `UrlbarProviderQuickSuggest`.
+ *
+ * - Your feature will automatically get its own logger.
+ *
+ * To register your subclass with `QuickSuggest`, add it to the `FEATURES` const
+ * in QuickSuggest.sys.mjs.
+ */
+export class BaseFeature {
+  /**
+   * {boolean}
+   *   Whether the feature should be enabled. Typically the subclass will check
+   *   the values of one or more Nimbus variables or preferences. `QuickSuggest`
+   *   will access this getter only when the quick suggest feature as a whole is
+   *   enabled. Otherwise the subclass feature will be disabled automatically.
+   */
+  get shouldEnable() {
+    throw new Error("`shouldEnable` must be overridden");
+  }
+
+  /**
+   * @returns {Array}
+   *   If the subclass's `shouldEnable` implementation depends on preferences
+   *   instead of Nimbus variables, the subclass should override this getter and
+   *   return their names in this array so that `enable()` can be called when
+   *   they change. Names should be in the same format that `UrlbarPrefs.get()`
+   *   expects.
+   */
+  get enablingPreferences() {
+    return null;
+  }
+
+  /**
+   * This method should initialize or uninitialize any state related to the
+   * feature.
+   *
+   * @param {boolean} enabled
+   *   Whether the feature should be enabled or not.
+   */
+  enable(enabled) {}
+
+  /**
+   * If the feature manages suggestions from remote settings that should be
+   * returned by UrlbarProviderQuickSuggest, the subclass should override this
+   * method. It should return remote settings suggestions matching the given
+   * search string.
+   *
+   * @param {string} searchString
+   *   The search string.
+   * @returns {Array}
+   *   An array of matching suggestions, or null if not implemented.
+   */
+  async queryRemoteSettings(searchString) {
+    return null;
+  }
+
+  /**
+   * If the feature manages data in remote settings, the subclass should
+   * override this method. It should fetch the data and build whatever data
+   * structures are necessary to support the feature.
+   *
+   * @param {RemoteSettings} rs
+   *   The `RemoteSettings` client object.
+   */
+  async onRemoteSettingsSync(rs) {}
+
+  /**
+   * If the feature corresponds to a type of suggestion, the subclass should
+   * override this method. It should return a new `UrlbarResult` for a given
+   * suggestion, which can come from either remote settings or Merino.
+   *
+   * @param {UrlbarQueryContext} queryContext
+   *   The query context.
+   * @param {object} suggestion
+   *   The suggestion from either remote settings or Merino.
+   * @param {string} searchString
+   *   The search string that was used to fetch the suggestion. It may be
+   *   different from `queryContext.searchString` due to trimming, lower-casing,
+   *   etc. This is included as a param in case it's useful.
+   * @returns {UrlbarResult}
+   *   A new result for the suggestion.
+   */
+  async makeResult(queryContext, suggestion, searchString) {
+    return null;
+  }
+
+  // Methods not designed for overriding below
+
+  /**
+   * @returns {Logger}
+   *   The feature's logger.
+   */
+  get logger() {
+    if (!this._logger) {
+      this._logger = lazy.UrlbarUtils.getLogger({
+        prefix: `QuickSuggest.${this.name}`,
+      });
+    }
+    return this._logger;
+  }
+
+  /**
+   * @returns {boolean}
+   *   Whether the feature is enabled. The enabled status is automatically
+   *   managed by `QuickSuggest` and subclasses should not override this.
+   */
+  get isEnabled() {
+    return this.#isEnabled;
+  }
+
+  /**
+   * @returns {string}
+   *   The feature's name.
+   */
+  get name() {
+    return this.constructor.name;
+  }
+
+  /**
+   * Enables or disables the feature according to `shouldEnable` and whether
+   * quick suggest is enabled. If the feature is already enabled appropriately,
+   * does nothing.
+   */
+  update() {
+    let enable =
+      lazy.UrlbarPrefs.get("quickSuggestEnabled") && this.shouldEnable;
+    if (enable != this.isEnabled) {
+      this.logger.info(`Setting enabled = ${enable}`);
+      this.enable(enable);
+      this.#isEnabled = enable;
+    }
+  }
+
+  #isEnabled = false;
+}