Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2096 insertions, 0 deletions

diff --git a/browser/components/newtab/lib/ASRouter.jsm b/browser/components/newtab/lib/ASRouter.jsm
new file mode 100644
index 0000000000..964fa1f011
--- /dev/null
+++ b/browser/components/newtab/lib/ASRouter.jsm
@@ -0,0 +1,2096 @@
+/* vim: set ts=2 sw=2 sts=2 et tw=80: */
+/* 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/. */
+"use strict";
+
+const { XPCOMUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/XPCOMUtils.sys.mjs"
+);
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+const lazy = {};
+XPCOMUtils.defineLazyModuleGetters(lazy, {
+  SnippetsTestMessageProvider:
+    "resource://activity-stream/lib/SnippetsTestMessageProvider.jsm",
+  PanelTestProvider: "resource://activity-stream/lib/PanelTestProvider.jsm",
+  Spotlight: "resource://activity-stream/lib/Spotlight.jsm",
+  ToastNotification: "resource://activity-stream/lib/ToastNotification.jsm",
+  ToolbarBadgeHub: "resource://activity-stream/lib/ToolbarBadgeHub.jsm",
+  ToolbarPanelHub: "resource://activity-stream/lib/ToolbarPanelHub.jsm",
+  MomentsPageHub: "resource://activity-stream/lib/MomentsPageHub.jsm",
+  InfoBar: "resource://activity-stream/lib/InfoBar.jsm",
+  ASRouterTargeting: "resource://activity-stream/lib/ASRouterTargeting.jsm",
+  ASRouterPreferences: "resource://activity-stream/lib/ASRouterPreferences.jsm",
+  TARGETING_PREFERENCES:
+    "resource://activity-stream/lib/ASRouterPreferences.jsm",
+  ASRouterTriggerListeners:
+    "resource://activity-stream/lib/ASRouterTriggerListeners.jsm",
+  KintoHttpClient: "resource://services-common/kinto-http-client.js",
+  Downloader: "resource://services-settings/Attachments.jsm",
+  RemoteImages: "resource://activity-stream/lib/RemoteImages.jsm",
+  RemoteL10n: "resource://activity-stream/lib/RemoteL10n.jsm",
+  ExperimentAPI: "resource://nimbus/ExperimentAPI.jsm",
+  setTimeout: "resource://gre/modules/Timer.jsm",
+  NimbusFeatures: "resource://nimbus/ExperimentAPI.jsm",
+  SpecialMessageActions:
+    "resource://messaging-system/lib/SpecialMessageActions.jsm",
+  TargetingContext: "resource://messaging-system/targeting/Targeting.jsm",
+  Utils: "resource://services-settings/Utils.jsm",
+  MacAttribution: "resource:///modules/MacAttribution.jsm",
+});
+XPCOMUtils.defineLazyServiceGetters(lazy, {
+  BrowserHandler: ["@mozilla.org/browser/clh;1", "nsIBrowserHandler"],
+});
+const { actionCreators: ac } = ChromeUtils.importESModule(
+  "resource://activity-stream/common/Actions.sys.mjs"
+);
+
+const { CFRMessageProvider } = ChromeUtils.import(
+  "resource://activity-stream/lib/CFRMessageProvider.jsm"
+);
+const { OnboardingMessageProvider } = ChromeUtils.import(
+  "resource://activity-stream/lib/OnboardingMessageProvider.jsm"
+);
+const { RemoteSettings } = ChromeUtils.import(
+  "resource://services-settings/remote-settings.js"
+);
+const { CFRPageActions } = ChromeUtils.import(
+  "resource://activity-stream/lib/CFRPageActions.jsm"
+);
+const { AttributionCode } = ChromeUtils.import(
+  "resource:///modules/AttributionCode.jsm"
+);
+
+// List of hosts for endpoints that serve router messages.
+// Key is allowed host, value is a name for the endpoint host.
+const DEFAULT_ALLOWLIST_HOSTS = {
+  "activity-stream-icons.services.mozilla.com": "production",
+  "snippets-admin.mozilla.org": "preview",
+};
+const SNIPPETS_ENDPOINT_ALLOWLIST =
+  "browser.newtab.activity-stream.asrouter.allowHosts";
+// Max possible impressions cap for any message
+const MAX_MESSAGE_LIFETIME_CAP = 100;
+
+const LOCAL_MESSAGE_PROVIDERS = {
+  OnboardingMessageProvider,
+  CFRMessageProvider,
+};
+const STARTPAGE_VERSION = "6";
+
+// Remote Settings
+const RS_MAIN_BUCKET = "main";
+const RS_COLLECTION_L10N = "ms-language-packs"; // "ms" stands for Messaging System
+const RS_PROVIDERS_WITH_L10N = ["cfr"];
+const RS_FLUENT_VERSION = "v1";
+const RS_FLUENT_RECORD_PREFIX = `cfr-${RS_FLUENT_VERSION}`;
+const RS_DOWNLOAD_MAX_RETRIES = 2;
+// This is the list of providers for which we want to cache the targeting
+// expression result and reuse between calls. Cache duration is defined in
+// ASRouterTargeting where evaluation takes place.
+const JEXL_PROVIDER_CACHE = new Set(["snippets"]);
+
+// To observe the app locale change notification.
+const TOPIC_INTL_LOCALE_CHANGED = "intl:app-locales-changed";
+const TOPIC_EXPERIMENT_FORCE_ENROLLED = "nimbus:force-enroll";
+// To observe the pref that controls if ASRouter should use the remote Fluent files for l10n.
+const USE_REMOTE_L10N_PREF =
+  "browser.newtabpage.activity-stream.asrouter.useRemoteL10n";
+
+const MESSAGING_EXPERIMENTS_DEFAULT_FEATURES = [
+  "cfr",
+  "fxms-message-1",
+  "fxms-message-2",
+  "fxms-message-3",
+  "infobar",
+  "moments-page",
+  "pbNewtab",
+  "spotlight",
+];
+
+// Experiment groups that need to report the reach event in Messaging-Experiments.
+// If you're adding new groups to it, make sure they're also added in the
+// `messaging_experiments.reach.objects` defined in "toolkit/components/telemetry/Events.yaml"
+const REACH_EVENT_GROUPS = ["cfr", "moments-page", "infobar", "spotlight"];
+const REACH_EVENT_CATEGORY = "messaging_experiments";
+const REACH_EVENT_METHOD = "reach";
+
+const MessageLoaderUtils = {
+  STARTPAGE_VERSION,
+  REMOTE_LOADER_CACHE_KEY: "RemoteLoaderCache",
+  _errors: [],
+
+  reportError(e) {
+    console.error(e);
+    this._errors.push({
+      timestamp: new Date(),
+      error: { message: e.toString(), stack: e.stack },
+    });
+  },
+
+  get errors() {
+    const errors = this._errors;
+    this._errors = [];
+    return errors;
+  },
+
+  /**
+   * _localLoader - Loads messages for a local provider (i.e. one that lives in mozilla central)
+   *
+   * @param {obj} provider An AS router provider
+   * @param {Array} provider.messages An array of messages
+   * @returns {Array} the array of messages
+   */
+  _localLoader(provider) {
+    return provider.messages;
+  },
+
+  async _remoteLoaderCache(storage) {
+    let allCached;
+    try {
+      allCached =
+        (await storage.get(MessageLoaderUtils.REMOTE_LOADER_CACHE_KEY)) || {};
+    } catch (e) {
+      // istanbul ignore next
+      MessageLoaderUtils.reportError(e);
+      // istanbul ignore next
+      allCached = {};
+    }
+    return allCached;
+  },
+
+  /**
+   * _remoteLoader - Loads messages for a remote provider
+   *
+   * @param {obj} provider An AS router provider
+   * @param {string} provider.url An endpoint that returns an array of messages as JSON
+   * @param {obj} options.storage A storage object with get() and set() methods for caching.
+   * @returns {Promise} resolves with an array of messages, or an empty array if none could be fetched
+   */
+  async _remoteLoader(provider, options) {
+    let remoteMessages = [];
+    if (provider.url) {
+      const allCached = await MessageLoaderUtils._remoteLoaderCache(
+        options.storage
+      );
+      const cached = allCached[provider.id];
+      let etag;
+
+      if (
+        cached &&
+        cached.url === provider.url &&
+        cached.version === STARTPAGE_VERSION
+      ) {
+        const { lastFetched, messages } = cached;
+        if (
+          !MessageLoaderUtils.shouldProviderUpdate({
+            ...provider,
+            lastUpdated: lastFetched,
+          })
+        ) {
+          // Cached messages haven't expired, return early.
+          return messages;
+        }
+        etag = cached.etag;
+        remoteMessages = messages;
+      }
+
+      let headers = new Headers();
+      if (etag) {
+        headers.set("If-None-Match", etag);
+      }
+
+      let response;
+      try {
+        response = await fetch(provider.url, {
+          headers,
+          credentials: "omit",
+        });
+      } catch (e) {
+        MessageLoaderUtils.reportError(e);
+      }
+      if (
+        response &&
+        response.ok &&
+        response.status >= 200 &&
+        response.status < 400
+      ) {
+        let jsonResponse;
+        try {
+          jsonResponse = await response.json();
+        } catch (e) {
+          MessageLoaderUtils.reportError(e);
+          return remoteMessages;
+        }
+        if (jsonResponse && jsonResponse.messages) {
+          remoteMessages = jsonResponse.messages.map(msg => ({
+            ...msg,
+            provider_url: provider.url,
+          }));
+
+          // Cache the results if this isn't a preview URL.
+          if (provider.updateCycleInMs > 0) {
+            etag = response.headers.get("ETag");
+            const cacheInfo = {
+              messages: remoteMessages,
+              etag,
+              lastFetched: Date.now(),
+              version: STARTPAGE_VERSION,
+            };
+
+            options.storage.set(MessageLoaderUtils.REMOTE_LOADER_CACHE_KEY, {
+              ...allCached,
+              [provider.id]: cacheInfo,
+            });
+          }
+        } else {
+          MessageLoaderUtils.reportError(
+            `No messages returned from ${provider.url}.`
+          );
+        }
+      } else if (response) {
+        MessageLoaderUtils.reportError(
+          `Invalid response status ${response.status} from ${provider.url}.`
+        );
+      }
+    }
+    return remoteMessages;
+  },
+
+  /**
+   * _remoteSettingsLoader - Loads messages for a RemoteSettings provider
+   *
+   * Note:
+   * 1). The "cfr" provider requires the Fluent file for l10n, so there is
+   * another file downloading phase for those two providers after their messages
+   * are successfully fetched from Remote Settings. Currently, they share the same
+   * attachment of the record "${RS_FLUENT_RECORD_PREFIX}-${locale}" in the
+   * "ms-language-packs" collection. E.g. for "en-US" with version "v1",
+   * the Fluent file is attched to the record with ID "cfr-v1-en-US".
+   *
+   * 2). The Remote Settings downloader is able to detect the duplicate download
+   * requests for the same attachment and ignore the redundent requests automatically.
+   *
+   * @param {object} provider An AS router provider
+   * @param {string} provider.id The id of the provider
+   * @param {string} provider.collection Remote Settings collection name
+   * @param {object} options
+   * @param {function} options.dispatchCFRAction Action handler function
+   * @returns {Promise<object[]>} Resolves with an array of messages, or an
+   *                              empty array if none could be fetched
+   */
+  async _remoteSettingsLoader(provider, options) {
+    let messages = [];
+    if (provider.collection) {
+      try {
+        messages = await MessageLoaderUtils._getRemoteSettingsMessages(
+          provider.collection
+        );
+        if (!messages.length) {
+          MessageLoaderUtils._handleRemoteSettingsUndesiredEvent(
+            "ASR_RS_NO_MESSAGES",
+            provider.id,
+            options.dispatchCFRAction
+          );
+        } else if (
+          RS_PROVIDERS_WITH_L10N.includes(provider.id) &&
+          lazy.RemoteL10n.isLocaleSupported(MessageLoaderUtils.locale)
+        ) {
+          const recordId = `${RS_FLUENT_RECORD_PREFIX}-${MessageLoaderUtils.locale}`;
+          const kinto = new lazy.KintoHttpClient(lazy.Utils.SERVER_URL);
+          const record = await kinto
+            .bucket(RS_MAIN_BUCKET)
+            .collection(RS_COLLECTION_L10N)
+            .getRecord(recordId);
+          if (record && record.data) {
+            const downloader = new lazy.Downloader(
+              RS_MAIN_BUCKET,
+              RS_COLLECTION_L10N,
+              "browser",
+              "newtab"
+            );
+            // Await here in order to capture the exceptions for reporting.
+            await downloader.downloadToDisk(record.data, {
+              retries: RS_DOWNLOAD_MAX_RETRIES,
+            });
+            lazy.RemoteL10n.reloadL10n();
+          } else {
+            MessageLoaderUtils._handleRemoteSettingsUndesiredEvent(
+              "ASR_RS_NO_MESSAGES",
+              RS_COLLECTION_L10N,
+              options.dispatchCFRAction
+            );
+          }
+        }
+      } catch (e) {
+        MessageLoaderUtils._handleRemoteSettingsUndesiredEvent(
+          "ASR_RS_ERROR",
+          provider.id,
+          options.dispatchCFRAction
+        );
+        MessageLoaderUtils.reportError(e);
+      }
+    }
+    return messages;
+  },
+
+  /**
+   * Fetch messages from a given collection in Remote Settings.
+   *
+   * @param {string} collection The remote settings collection identifier
+   * @returns {Promise<object[]>} Resolves with an array of messages
+   */
+  _getRemoteSettingsMessages(collection) {
+    return RemoteSettings(collection).get();
+  },
+
+  /**
+   * Return messages from active Nimbus experiments and rollouts.
+   *
+   * @param {object} provider A messaging experiments provider.
+   * @param {string[]?} provider.featureIds
+   *                    An optional array of Nimbus feature IDs to check for
+   *                    enrollments. If not provided, we will fall back to the
+   *                    set of default features. Otherwise, if provided and
+   *                    empty, we will not ingest messages from any features.
+   *
+   * @return {object[]} The list of messages from active enrollments, as well as
+   *                    the messages defined in unenrolled branches so that they
+   *                    reach events can be recorded (if we record reach events
+   *                    for that feature).
+   */
+  async _experimentsAPILoader(provider) {
+    // Allow tests to override the set of featureIds
+    const featureIds = Array.isArray(provider.featureIds)
+      ? provider.featureIds
+      : MESSAGING_EXPERIMENTS_DEFAULT_FEATURES;
+    let experiments = [];
+    for (const featureId of featureIds) {
+      let featureAPI = lazy.NimbusFeatures[featureId];
+      let experimentData = lazy.ExperimentAPI.getExperimentMetaData({
+        featureId,
+      });
+
+      // We are not enrolled in any experiment or rollout for this feature, so
+      // we can skip the feature.
+      if (
+        !experimentData &&
+        !lazy.ExperimentAPI.getRolloutMetaData({ featureId })
+      ) {
+        continue;
+      }
+
+      let message = featureAPI.getAllVariables();
+
+      if (message?.id) {
+        // Cache the Nimbus feature ID on the message because there is not a 1-1
+        // correspondance between templates and features. This is used when
+        // recording expose events (see |sendTriggerMessage|).
+        message._nimbusFeature = featureId;
+        experiments.push(message);
+      }
+
+      if (!REACH_EVENT_GROUPS.includes(featureId)) {
+        continue;
+      }
+
+      // If we are in a rollout, we do not have sibling branches.
+      if (experimentData) {
+        // Check other sibling branches for triggers, add them to the return
+        // array if found any. The `forReachEvent` label is used to identify
+        // those branches so that they would only used to record the Reach
+        // event.
+        const branches =
+          (await lazy.ExperimentAPI.getAllBranches(experimentData.slug)) || [];
+        for (const branch of branches) {
+          let branchValue = branch[featureId].value;
+          if (
+            branch.slug !== experimentData.branch.slug &&
+            branchValue?.trigger
+          ) {
+            experiments.push({
+              forReachEvent: { sent: false, group: featureId },
+              experimentSlug: experimentData.slug,
+              branchSlug: branch.slug,
+              ...branchValue,
+            });
+          }
+        }
+      }
+    }
+
+    return experiments;
+  },
+
+  _handleRemoteSettingsUndesiredEvent(event, providerId, dispatchCFRAction) {
+    if (dispatchCFRAction) {
+      dispatchCFRAction(
+        ac.ASRouterUserEvent({
+          action: "asrouter_undesired_event",
+          event,
+          message_id: "n/a",
+          event_context: providerId,
+        })
+      );
+    }
+  },
+
+  /**
+   * _getMessageLoader - return the right loading function given the provider's type
+   *
+   * @param {obj} provider An AS Router provider
+   * @returns {func} A loading function
+   */
+  _getMessageLoader(provider) {
+    switch (provider.type) {
+      case "remote":
+        return this._remoteLoader;
+      case "remote-settings":
+        return this._remoteSettingsLoader;
+      case "remote-experiments":
+        return this._experimentsAPILoader;
+      case "local":
+      default:
+        return this._localLoader;
+    }
+  },
+
+  /**
+   * shouldProviderUpdate - Given the current time, should a provider update its messages?
+   *
+   * @param {any} provider An AS Router provider
+   * @param {int} provider.updateCycleInMs The number of milliseconds we should wait between updates
+   * @param {Date} provider.lastUpdated If the provider has been updated, the time the last update occurred
+   * @param {Date} currentTime The time we should check against. (defaults to Date.now())
+   * @returns {bool} Should an update happen?
+   */
+  shouldProviderUpdate(provider, currentTime = Date.now()) {
+    return (
+      !(provider.lastUpdated >= 0) ||
+      currentTime - provider.lastUpdated > provider.updateCycleInMs
+    );
+  },
+
+  async _loadDataForProvider(provider, options) {
+    const loader = this._getMessageLoader(provider);
+    let messages = await loader(provider, options);
+    // istanbul ignore if
+    if (!messages) {
+      messages = [];
+      MessageLoaderUtils.reportError(
+        new Error(
+          `Tried to load messages for ${provider.id} but the result was not an Array.`
+        )
+      );
+    }
+
+    return { messages };
+  },
+
+  /**
+   * loadMessagesForProvider - Load messages for a provider, given the provider's type.
+   *
+   * @param {obj} provider An AS Router provider
+   * @param {string} provider.type An AS Router provider type (defaults to "local")
+   * @param {obj} options.storage A storage object with get() and set() methods for caching.
+   * @param {func} options.dispatchCFRAction dispatch an action the main AS Store
+   * @returns {obj} Returns an object with .messages (an array of messages) and .lastUpdated (the time the messages were updated)
+   */
+  async loadMessagesForProvider(provider, options) {
+    let { messages } = await this._loadDataForProvider(provider, options);
+    // Filter out messages we temporarily want to exclude
+    if (provider.exclude && provider.exclude.length) {
+      messages = messages.filter(
+        message => !provider.exclude.includes(message.id)
+      );
+    }
+    const lastUpdated = Date.now();
+    return {
+      messages: messages
+        .map(messageData => {
+          const message = {
+            weight: 100,
+            ...messageData,
+            groups: messageData.groups || [],
+            provider: provider.id,
+          };
+
+          return message;
+        })
+        .filter(message => message.weight > 0),
+      lastUpdated,
+      errors: MessageLoaderUtils.errors,
+    };
+  },
+
+  /**
+   * cleanupCache - Removes cached data of removed providers.
+   *
+   * @param {Array} providers A list of activer AS Router providers
+   */
+  async cleanupCache(providers, storage) {
+    const ids = providers.filter(p => p.type === "remote").map(p => p.id);
+    const cache = await MessageLoaderUtils._remoteLoaderCache(storage);
+    let dirty = false;
+    for (let id in cache) {
+      if (!ids.includes(id)) {
+        delete cache[id];
+        dirty = true;
+      }
+    }
+    if (dirty) {
+      await storage.set(MessageLoaderUtils.REMOTE_LOADER_CACHE_KEY, cache);
+    }
+  },
+
+  /**
+   * The locale to use for RemoteL10n.
+   *
+   * This may map the app's actual locale into something that RemoteL10n
+   * supports.
+   */
+  get locale() {
+    const localeMap = {
+      "ja-JP-macos": "ja-JP-mac",
+
+      // While it's not a valid locale, "und" is commonly observed on
+      // Linux platforms. Per l10n team, it's reasonable to fallback to
+      // "en-US", therefore, we should allow the fetch for it.
+      und: "en-US",
+    };
+
+    const locale = Services.locale.appLocaleAsBCP47;
+    return localeMap[locale] ?? locale;
+  },
+};
+
+/**
+ * @class _ASRouter - Keeps track of all messages, UI surfaces, and
+ * handles blocking, rotation, etc. Inspecting ASRouter.state will
+ * tell you what the current displayed message is in all UI surfaces.
+ *
+ * Note: This is written as a constructor rather than just a plain object
+ * so that it can be more easily unit tested.
+ */
+class _ASRouter {
+  constructor(localProviders = LOCAL_MESSAGE_PROVIDERS) {
+    this.initialized = false;
+    this.clearChildMessages = null;
+    this.clearChildProviders = null;
+    this.updateAdminState = null;
+    this.sendTelemetry = null;
+    this.dispatchCFRAction = null;
+    this._storage = null;
+    this._resetInitialization();
+    this._state = {
+      providers: [],
+      messageBlockList: [],
+      messageImpressions: {},
+      messages: [],
+      groups: [],
+      errors: [],
+      localeInUse: Services.locale.appLocaleAsBCP47,
+    };
+    this._experimentChangedListeners = new Map();
+    this._triggerHandler = this._triggerHandler.bind(this);
+    this._localProviders = localProviders;
+    this.blockMessageById = this.blockMessageById.bind(this);
+    this.unblockMessageById = this.unblockMessageById.bind(this);
+    this.handleMessageRequest = this.handleMessageRequest.bind(this);
+    this.addImpression = this.addImpression.bind(this);
+    this._handleTargetingError = this._handleTargetingError.bind(this);
+    this.onPrefChange = this.onPrefChange.bind(this);
+    this._onLocaleChanged = this._onLocaleChanged.bind(this);
+    this.isUnblockedMessage = this.isUnblockedMessage.bind(this);
+    this.unblockAll = this.unblockAll.bind(this);
+    this.forceWNPanel = this.forceWNPanel.bind(this);
+    this._onExperimentForceEnrolled = this._onExperimentForceEnrolled.bind(
+      this
+    );
+    this.forcePBWindow = this.forcePBWindow.bind(this);
+    Services.telemetry.setEventRecordingEnabled(REACH_EVENT_CATEGORY, true);
+  }
+
+  async onPrefChange(prefName) {
+    if (lazy.TARGETING_PREFERENCES.includes(prefName)) {
+      let invalidMessages = [];
+      // Notify all tabs of messages that have become invalid after pref change
+      const context = this._getMessagesContext();
+      const targetingContext = new lazy.TargetingContext(context);
+
+      for (const msg of this.state.messages.filter(this.isUnblockedMessage)) {
+        if (!msg.targeting) {
+          continue;
+        }
+        const isMatch = await targetingContext.evalWithDefault(msg.targeting);
+        if (!isMatch) {
+          invalidMessages.push(msg.id);
+        }
+      }
+      this.clearChildMessages(invalidMessages);
+    } else {
+      // Update message providers and fetch new messages on pref change
+      this._loadLocalProviders();
+      let invalidProviders = await this._updateMessageProviders();
+      if (invalidProviders.length) {
+        this.clearChildProviders(invalidProviders);
+      }
+      await this.loadMessagesFromAllProviders();
+      // Any change in user prefs can disable or enable groups
+      await this.setState(state => ({
+        groups: state.groups.map(this._checkGroupEnabled),
+      }));
+    }
+  }
+
+  // Fetch and decode the message provider pref JSON, and update the message providers
+  async _updateMessageProviders() {
+    lazy.ASRouterPreferences.console.debug("entering updateMessageProviders");
+
+    const previousProviders = this.state.providers;
+    const providers = await Promise.all(
+      [
+        // If we have added a `preview` provider, hold onto it
+        ...previousProviders.filter(p => p.id === "preview"),
+        // The provider should be enabled and not have a user preference set to false
+        ...lazy.ASRouterPreferences.providers.filter(
+          p =>
+            p.enabled &&
+            lazy.ASRouterPreferences.getUserPreference(p.id) !== false
+        ),
+      ].map(async _provider => {
+        // make a copy so we don't modify the source of the pref
+        const provider = { ..._provider };
+
+        if (provider.type === "local" && !provider.messages) {
+          // Get the messages from the local message provider
+          const localProvider = this._localProviders[provider.localProvider];
+          provider.messages = [];
+          if (localProvider) {
+            provider.messages = await localProvider.getMessages();
+          }
+        }
+        if (provider.type === "remote" && provider.url) {
+          provider.url = provider.url.replace(
+            /%STARTPAGE_VERSION%/g,
+            STARTPAGE_VERSION
+          );
+          provider.url = Services.urlFormatter.formatURL(provider.url);
+        }
+        if (provider.id === "messaging-experiments") {
+          // By default, the messaging-experiments provider lacks a featureIds
+          // property, so fall back to the list of default features.
+          if (!provider.featureIds) {
+            provider.featureIds = MESSAGING_EXPERIMENTS_DEFAULT_FEATURES;
+          }
+        }
+        // Reset provider update timestamp to force message refresh
+        provider.lastUpdated = undefined;
+        return provider;
+      })
+    );
+
+    const providerIDs = providers.map(p => p.id);
+    let invalidProviders = [];
+
+    // Clear old messages for providers that are no longer enabled
+    for (const prevProvider of previousProviders) {
+      if (!providerIDs.includes(prevProvider.id)) {
+        invalidProviders.push(prevProvider.id);
+      }
+    }
+
+    {
+      // If the feature IDs of the messaging-experiments provider has changed,
+      // then we need to update which features for which we are listening to
+      // changes.
+      const prevExpts = previousProviders.find(
+        p => p.id === "messaging-experiments"
+      );
+      const expts = providers.find(p => p.id === "messaging-experiments");
+
+      this._onFeatureListChanged(
+        prevExpts?.enabled ? prevExpts.featureIds : [],
+        expts?.enabled ? expts.featureIds : []
+      );
+    }
+
+    return this.setState(prevState => ({
+      providers,
+      // Clear any messages from removed providers
+      messages: [
+        ...prevState.messages.filter(message =>
+          providerIDs.includes(message.provider)
+        ),
+      ],
+    })).then(() => invalidProviders);
+  }
+
+  get state() {
+    return this._state;
+  }
+
+  set state(value) {
+    throw new Error(
+      "Do not modify this.state directy. Instead, call this.setState(newState)"
+    );
+  }
+
+  /**
+   * _resetInitialization - adds the following to the instance:
+   *  .initialized {bool}            Has AS Router been initialized?
+   *  .waitForInitialized {Promise}  A promise that resolves when initializion is complete
+   *  ._finishInitializing {func}    A function that, when called, resolves the .waitForInitialized
+   *                                 promise and sets .initialized to true.
+   * @memberof _ASRouter
+   */
+  _resetInitialization() {
+    this.initialized = false;
+    this.initializing = false;
+    this.waitForInitialized = new Promise(resolve => {
+      this._finishInitializing = () => {
+        this.initialized = true;
+        this.initializing = false;
+        resolve();
+      };
+    });
+  }
+
+  /**
+   * Check all provided groups are enabled.
+   * @param groups Set of groups to verify
+   * @returns bool
+   */
+  hasGroupsEnabled(groups = []) {
+    return this.state.groups
+      .filter(({ id }) => groups.includes(id))
+      .every(({ enabled }) => enabled);
+  }
+
+  /**
+   * Verify that the provider block the message through the `exclude` field
+   * @param message Message to verify
+   * @returns bool
+   */
+  isExcludedByProvider(message) {
+    // preview snippets are never excluded
+    if (message.provider === "preview") {
+      return false;
+    }
+    const provider = this.state.providers.find(p => p.id === message.provider);
+    if (!provider) {
+      return true;
+    }
+    if (provider.exclude) {
+      return provider.exclude.includes(message.id);
+    }
+    return false;
+  }
+
+  /**
+   * Takes a group and sets the correct `enabled` state based on message config
+   * and user preferences
+   *
+   * @param {GroupConfig} group
+   * @returns {GroupConfig}
+   */
+  _checkGroupEnabled(group) {
+    return {
+      ...group,
+      enabled:
+        group.enabled &&
+        // And if defined user preferences are true. If multiple prefs are
+        // defined then at least one has to be enabled.
+        (Array.isArray(group.userPreferences)
+          ? group.userPreferences.some(pref =>
+              lazy.ASRouterPreferences.getUserPreference(pref)
+            )
+          : true),
+    };
+  }
+
+  /**
+   * Fetch all message groups and update Router.state.groups.
+   * There are two cases to consider:
+   * 1. The provider needs to update as determined by the update cycle
+   * 2. Some pref change occured which could invalidate one of the existing
+   *    groups.
+   */
+  async loadAllMessageGroups() {
+    const provider = this.state.providers.find(
+      p =>
+        p.id === "message-groups" && MessageLoaderUtils.shouldProviderUpdate(p)
+    );
+    let remoteMessages = null;
+    if (provider) {
+      const { messages } = await MessageLoaderUtils._loadDataForProvider(
+        provider,
+        {
+          storage: this._storage,
+          dispatchCFRAction: this.dispatchCFRAction,
+        }
+      );
+      remoteMessages = messages;
+    }
+    await this.setState(state => ({
+      // If fetching remote messages fails we default to existing state.groups.
+      groups: (remoteMessages || state.groups).map(this._checkGroupEnabled),
+    }));
+  }
+
+  /**
+   * loadMessagesFromAllProviders - Loads messages from all providers if they require updates.
+   *                                Checks the .lastUpdated field on each provider to see if updates are needed
+   * @param toUpdate  An optional list of providers to update. This overrides
+   *                  the checks to determine which providers to update.
+   * @memberof _ASRouter
+   */
+  async loadMessagesFromAllProviders(toUpdate = undefined) {
+    const needsUpdate = Array.isArray(toUpdate)
+      ? toUpdate
+      : this.state.providers.filter(provider =>
+          MessageLoaderUtils.shouldProviderUpdate(provider)
+        );
+    lazy.ASRouterPreferences.console.debug(
+      "entering loadMessagesFromAllProviders"
+    );
+
+    await this.loadAllMessageGroups();
+    // Don't do extra work if we don't need any updates
+    if (needsUpdate.length) {
+      let newState = { messages: [], providers: [] };
+      for (const provider of this.state.providers) {
+        if (needsUpdate.includes(provider)) {
+          const {
+            messages,
+            lastUpdated,
+            errors,
+          } = await MessageLoaderUtils.loadMessagesForProvider(provider, {
+            storage: this._storage,
+            dispatchCFRAction: this.dispatchCFRAction,
+          });
+          newState.providers.push({ ...provider, lastUpdated, errors });
+          newState.messages = [...newState.messages, ...messages];
+        } else {
+          // Skip updating this provider's messages if no update is required
+          let messages = this.state.messages.filter(
+            msg => msg.provider === provider.id
+          );
+          newState.providers.push(provider);
+          newState.messages = [...newState.messages, ...messages];
+        }
+      }
+
+      // Some messages have triggers that require us to initalise trigger listeners
+      const unseenListeners = new Set(lazy.ASRouterTriggerListeners.keys());
+      for (const { trigger } of newState.messages) {
+        if (trigger && lazy.ASRouterTriggerListeners.has(trigger.id)) {
+          lazy.ASRouterTriggerListeners.get(trigger.id).init(
+            this._triggerHandler,
+            trigger.params,
+            trigger.patterns
+          );
+          unseenListeners.delete(trigger.id);
+        }
+      }
+      // We don't need these listeners, but they may have previously been
+      // initialised, so uninitialise them
+      for (const triggerID of unseenListeners) {
+        lazy.ASRouterTriggerListeners.get(triggerID).uninit();
+      }
+
+      // We don't want to cache preview endpoints, remove them after messages are fetched
+      await this.setState(this._removePreviewEndpoint(newState));
+      await this.cleanupImpressions();
+    }
+    return this.state;
+  }
+
+  async _maybeUpdateL10nAttachment() {
+    const { localeInUse } = this.state.localeInUse;
+    const newLocale = Services.locale.appLocaleAsBCP47;
+    if (newLocale !== localeInUse) {
+      const providers = [...this.state.providers];
+      let needsUpdate = false;
+      providers.forEach(provider => {
+        if (RS_PROVIDERS_WITH_L10N.includes(provider.id)) {
+          // Force to refresh the messages as well as the attachment.
+          provider.lastUpdated = undefined;
+          needsUpdate = true;
+        }
+      });
+      if (needsUpdate) {
+        await this.setState({
+          localeInUse: newLocale,
+          providers,
+        });
+        await this.loadMessagesFromAllProviders();
+      }
+    }
+    return this.state;
+  }
+
+  async _onLocaleChanged(subject, topic, data) {
+    await this._maybeUpdateL10nAttachment();
+  }
+
+  observe(aSubject, aTopic, aPrefName) {
+    switch (aPrefName) {
+      case USE_REMOTE_L10N_PREF:
+        CFRPageActions.reloadL10n();
+        break;
+    }
+  }
+
+  toWaitForInitFunc(func) {
+    return (...args) => this.waitForInitialized.then(() => func(...args));
+  }
+
+  /**
+   * init - Initializes the MessageRouter.
+   *
+   * @param {obj} parameters parameters to initialize ASRouter
+   * @memberof _ASRouter
+   */
+  async init({
+    storage,
+    sendTelemetry,
+    clearChildMessages,
+    clearChildProviders,
+    updateAdminState,
+    dispatchCFRAction,
+  }) {
+    if (this.initializing || this.initialized) {
+      return null;
+    }
+    this.initializing = true;
+    this._storage = storage;
+    this.ALLOWLIST_HOSTS = this._loadSnippetsAllowHosts();
+    this.clearChildMessages = this.toWaitForInitFunc(clearChildMessages);
+    this.clearChildProviders = this.toWaitForInitFunc(clearChildProviders);
+    // NOTE: This is only necessary to sync devtools and snippets when devtools is active.
+    this.updateAdminState = this.toWaitForInitFunc(updateAdminState);
+    this.sendTelemetry = sendTelemetry;
+    this.dispatchCFRAction = this.toWaitForInitFunc(dispatchCFRAction);
+
+    lazy.ASRouterPreferences.init();
+    lazy.ASRouterPreferences.addListener(this.onPrefChange);
+    lazy.ToolbarBadgeHub.init(this.waitForInitialized, {
+      handleMessageRequest: this.handleMessageRequest,
+      addImpression: this.addImpression,
+      blockMessageById: this.blockMessageById,
+      unblockMessageById: this.unblockMessageById,
+      sendTelemetry: this.sendTelemetry,
+    });
+    lazy.ToolbarPanelHub.init(this.waitForInitialized, {
+      getMessages: this.handleMessageRequest,
+      sendTelemetry: this.sendTelemetry,
+    });
+    lazy.MomentsPageHub.init(this.waitForInitialized, {
+      handleMessageRequest: this.handleMessageRequest,
+      addImpression: this.addImpression,
+      blockMessageById: this.blockMessageById,
+      sendTelemetry: this.sendTelemetry,
+    });
+
+    this._loadLocalProviders();
+
+    const messageBlockList =
+      (await this._storage.get("messageBlockList")) || [];
+    const messageImpressions =
+      (await this._storage.get("messageImpressions")) || {};
+    const groupImpressions =
+      (await this._storage.get("groupImpressions")) || {};
+    const previousSessionEnd =
+      (await this._storage.get("previousSessionEnd")) || 0;
+
+    await this.setState({
+      messageBlockList,
+      groupImpressions,
+      messageImpressions,
+      previousSessionEnd,
+      ...(lazy.ASRouterPreferences.specialConditions || {}),
+      initialized: false,
+    });
+    await this._updateMessageProviders();
+    await this.loadMessagesFromAllProviders();
+    await MessageLoaderUtils.cleanupCache(this.state.providers, storage);
+
+    lazy.SpecialMessageActions.blockMessageById = this.blockMessageById;
+    Services.obs.addObserver(this._onLocaleChanged, TOPIC_INTL_LOCALE_CHANGED);
+    Services.obs.addObserver(
+      this._onExperimentForceEnrolled,
+      TOPIC_EXPERIMENT_FORCE_ENROLLED
+    );
+    Services.prefs.addObserver(USE_REMOTE_L10N_PREF, this);
+    // sets .initialized to true and resolves .waitForInitialized promise
+    this._finishInitializing();
+    return this.state;
+  }
+
+  uninit() {
+    this._storage.set("previousSessionEnd", Date.now());
+
+    this.clearChildMessages = null;
+    this.clearChildProviders = null;
+    this.updateAdminState = null;
+    this.sendTelemetry = null;
+    this.dispatchCFRAction = null;
+
+    lazy.ASRouterPreferences.removeListener(this.onPrefChange);
+    lazy.ASRouterPreferences.uninit();
+    lazy.ToolbarPanelHub.uninit();
+    lazy.ToolbarBadgeHub.uninit();
+    lazy.MomentsPageHub.uninit();
+
+    // Uninitialise all trigger listeners
+    for (const listener of lazy.ASRouterTriggerListeners.values()) {
+      listener.uninit();
+    }
+    Services.obs.removeObserver(
+      this._onLocaleChanged,
+      TOPIC_INTL_LOCALE_CHANGED
+    );
+    Services.obs.removeObserver(
+      this._onExperimentForceEnrolled,
+      TOPIC_EXPERIMENT_FORCE_ENROLLED
+    );
+    Services.prefs.removeObserver(USE_REMOTE_L10N_PREF, this);
+    // If we added any CFR recommendations, they need to be removed
+    CFRPageActions.clearRecommendations();
+    this._resetInitialization();
+  }
+
+  setState(callbackOrObj) {
+    lazy.ASRouterPreferences.console.debug(
+      "in setState, callbackOrObj = ",
+      callbackOrObj
+    );
+    lazy.ASRouterPreferences.console.trace();
+    const newState =
+      typeof callbackOrObj === "function"
+        ? callbackOrObj(this.state)
+        : callbackOrObj;
+    this._state = {
+      ...this.state,
+      ...newState,
+    };
+    if (lazy.ASRouterPreferences.devtoolsEnabled) {
+      return this.updateTargetingParameters().then(state => {
+        this.updateAdminState(state);
+        return state;
+      });
+    }
+    return Promise.resolve(this.state);
+  }
+
+  updateTargetingParameters() {
+    return this.getTargetingParameters(
+      lazy.ASRouterTargeting.Environment,
+      this._getMessagesContext()
+    ).then(targetingParameters => ({
+      ...this.state,
+      providerPrefs: lazy.ASRouterPreferences.providers,
+      userPrefs: lazy.ASRouterPreferences.getAllUserPreferences(),
+      targetingParameters,
+      errors: this.errors,
+    }));
+  }
+
+  getMessageById(id) {
+    return this.state.messages.find(message => message.id === id);
+  }
+
+  _loadLocalProviders() {
+    // If we're in ASR debug mode add the local test providers
+    if (lazy.ASRouterPreferences.devtoolsEnabled) {
+      this._localProviders = {
+        ...this._localProviders,
+        SnippetsTestMessageProvider: lazy.SnippetsTestMessageProvider,
+        PanelTestProvider: lazy.PanelTestProvider,
+      };
+    }
+  }
+
+  /**
+   * Used by ASRouter Admin returns all ASRouterTargeting.Environment
+   * and ASRouter._getMessagesContext parameters and values
+   */
+  async getTargetingParameters(environment, localContext) {
+    const targetingParameters = {};
+    for (const param of Object.keys(environment)) {
+      targetingParameters[param] = await environment[param];
+    }
+    for (const param of Object.keys(localContext)) {
+      targetingParameters[param] = await localContext[param];
+    }
+
+    return targetingParameters;
+  }
+
+  _handleTargetingError(error, message) {
+    console.error(error);
+    this.dispatchCFRAction(
+      ac.ASRouterUserEvent({
+        message_id: message.id,
+        action: "asrouter_undesired_event",
+        event: "TARGETING_EXPRESSION_ERROR",
+        event_context: {},
+      })
+    );
+  }
+
+  // Return an object containing targeting parameters used to select messages
+  _getMessagesContext() {
+    const { messageImpressions, previousSessionEnd } = this.state;
+
+    return {
+      get messageImpressions() {
+        return messageImpressions;
+      },
+      get previousSessionEnd() {
+        return previousSessionEnd;
+      },
+    };
+  }
+
+  async evaluateExpression({ expression, context }) {
+    const targetingContext = new lazy.TargetingContext(context);
+    let evaluationStatus;
+    try {
+      evaluationStatus = {
+        result: await targetingContext.evalWithDefault(expression),
+        success: true,
+      };
+    } catch (e) {
+      evaluationStatus = { result: e.message, success: false };
+    }
+    return Promise.resolve({ evaluationStatus });
+  }
+
+  unblockAll() {
+    return this.setState({ messageBlockList: [] });
+  }
+
+  isUnblockedMessage(message) {
+    const { state } = this;
+    return (
+      !state.messageBlockList.includes(message.id) &&
+      (!message.campaign ||
+        !state.messageBlockList.includes(message.campaign)) &&
+      this.hasGroupsEnabled(message.groups) &&
+      !this.isExcludedByProvider(message)
+    );
+  }
+
+  // Work out if a message can be shown based on its and its provider's frequency caps.
+  isBelowFrequencyCaps(message) {
+    const { messageImpressions, groupImpressions } = this.state;
+    const impressionsForMessage = messageImpressions[message.id];
+
+    const _belowItemFrequencyCap = this._isBelowItemFrequencyCap(
+      message,
+      impressionsForMessage,
+      MAX_MESSAGE_LIFETIME_CAP
+    );
+    if (!_belowItemFrequencyCap) {
+      lazy.ASRouterPreferences.console.debug(
+        `isBelowFrequencyCaps: capped by item: `,
+        message,
+        "impressions =",
+        impressionsForMessage
+      );
+    }
+
+    const _belowGroupFrequencyCaps = message.groups.every(messageGroup => {
+      const belowThisGroupCap = this._isBelowItemFrequencyCap(
+        this.state.groups.find(({ id }) => id === messageGroup),
+        groupImpressions[messageGroup]
+      );
+
+      if (!belowThisGroupCap) {
+        lazy.ASRouterPreferences.console.debug(
+          `isBelowFrequencyCaps: ${message.id} capped by group ${messageGroup}`
+        );
+      } else {
+        lazy.ASRouterPreferences.console.debug(
+          `isBelowFrequencyCaps: ${message.id} allowed by group ${messageGroup}, groupImpressions = `,
+          groupImpressions
+        );
+      }
+
+      return belowThisGroupCap;
+    });
+
+    return _belowItemFrequencyCap && _belowGroupFrequencyCaps;
+  }
+
+  // Helper for isBelowFrecencyCaps - work out if the frequency cap for the given
+  //                                  item has been exceeded or not
+  _isBelowItemFrequencyCap(item, impressions, maxLifetimeCap = Infinity) {
+    if (item && item.frequency && impressions && impressions.length) {
+      if (
+        item.frequency.lifetime &&
+        impressions.length >= Math.min(item.frequency.lifetime, maxLifetimeCap)
+      ) {
+        lazy.ASRouterPreferences.console.debug(
+          `${item.id} capped by lifetime (${item.frequency.lifetime})`
+        );
+
+        return false;
+      }
+      if (item.frequency.custom) {
+        const now = Date.now();
+        for (const setting of item.frequency.custom) {
+          let { period } = setting;
+          const impressionsInPeriod = impressions.filter(t => now - t < period);
+          if (impressionsInPeriod.length >= setting.cap) {
+            lazy.ASRouterPreferences.console.debug(
+              `${item.id} capped by impressions (${impressionsInPeriod.length}) in period (${period}) >= ${setting.cap}`
+            );
+            return false;
+          }
+        }
+      }
+    }
+    return true;
+  }
+
+  async _extraTemplateStrings(originalMessage) {
+    let extraTemplateStrings;
+    let localProvider = this._findProvider(originalMessage.provider);
+    if (localProvider && localProvider.getExtraAttributes) {
+      extraTemplateStrings = await localProvider.getExtraAttributes();
+    }
+
+    return extraTemplateStrings;
+  }
+
+  _findProvider(providerID) {
+    return this._localProviders[
+      this.state.providers.find(i => i.id === providerID).localProvider
+    ];
+  }
+
+  routeCFRMessage(message, browser, trigger, force = false) {
+    if (!message) {
+      return { message: {} };
+    }
+
+    switch (message.template) {
+      case "whatsnew_panel_message":
+        if (force) {
+          lazy.ToolbarPanelHub.forceShowMessage(browser, message);
+        }
+        break;
+      case "cfr_doorhanger":
+      case "milestone_message":
+        if (force) {
+          CFRPageActions.forceRecommendation(
+            browser,
+            message,
+            this.dispatchCFRAction
+          );
+        } else {
+          CFRPageActions.addRecommendation(
+            browser,
+            trigger.param && trigger.param.host,
+            message,
+            this.dispatchCFRAction
+          );
+        }
+        break;
+      case "cfr_urlbar_chiclet":
+        if (force) {
+          CFRPageActions.forceRecommendation(
+            browser,
+            message,
+            this.dispatchCFRAction
+          );
+        } else {
+          CFRPageActions.addRecommendation(
+            browser,
+            null,
+            message,
+            this.dispatchCFRAction
+          );
+        }
+        break;
+      case "toolbar_badge":
+        lazy.ToolbarBadgeHub.registerBadgeNotificationListener(message, {
+          force,
+        });
+        break;
+      case "update_action":
+        lazy.MomentsPageHub.executeAction(message);
+        break;
+      case "infobar":
+        lazy.InfoBar.showInfoBarMessage(
+          browser,
+          message,
+          this.dispatchCFRAction
+        );
+        break;
+      case "spotlight":
+        lazy.Spotlight.showSpotlightDialog(
+          browser,
+          message,
+          this.dispatchCFRAction
+        );
+        break;
+      case "toast_notification":
+        lazy.ToastNotification.showToastNotification(
+          message,
+          this.dispatchCFRAction
+        );
+        break;
+    }
+
+    return { message };
+  }
+
+  addImpression(message) {
+    lazy.ASRouterPreferences.console.debug(
+      `entering addImpression for ${message.id}`
+    );
+
+    const groupsWithFrequency = this.state.groups.filter(
+      ({ frequency, id }) => frequency && message.groups.includes(id)
+    );
+    // We only need to store impressions for messages that have frequency, or
+    // that have providers that have frequency
+    if (message.frequency || groupsWithFrequency.length) {
+      const time = Date.now();
+      return this.setState(state => {
+        const messageImpressions = this._addImpressionForItem(
+          state.messageImpressions,
+          message,
+          "messageImpressions",
+          time
+        );
+        // Initialize this with state.groupImpressions, and then assign the
+        // newly-updated copy to it during each iteration so that
+        // all the changes get captured and either returned or passed into the
+        // _addImpressionsForItem call on the next iteration.
+        let { groupImpressions } = state;
+        for (const group of groupsWithFrequency) {
+          groupImpressions = this._addImpressionForItem(
+            groupImpressions,
+            group,
+            "groupImpressions",
+            time
+          );
+        }
+
+        return { messageImpressions, groupImpressions };
+      });
+    }
+    return Promise.resolve();
+  }
+
+  // Helper for addImpression - calculate the updated impressions object for the given
+  //                            item, then store it and return it
+  _addImpressionForItem(currentImpressions, item, impressionsString, time) {
+    // The destructuring here is to avoid mutating passed parameters
+    // (see https://redux.js.org/recipes/structuring-reducers/prerequisite-concepts#immutable-data-management)
+    const impressions = { ...currentImpressions };
+    if (item.frequency) {
+      impressions[item.id] = impressions[item.id]
+        ? [...impressions[item.id]]
+        : [];
+      impressions[item.id].push(time);
+      lazy.ASRouterPreferences.console.debug(
+        item.id,
+        "impression added, impressions[item.id]: ",
+        impressions[item.id]
+      );
+
+      this._storage.set(impressionsString, impressions);
+    }
+    return impressions;
+  }
+
+  /**
+   * getLongestPeriod
+   *
+   * @param {obj} item Either an ASRouter message or an ASRouter provider
+   * @returns {int|null} if the item has custom frequency caps, the longest period found in the list of caps.
+                         if the item has no custom frequency caps, null
+   * @memberof _ASRouter
+   */
+  getLongestPeriod(item) {
+    if (!item.frequency || !item.frequency.custom) {
+      return null;
+    }
+    return item.frequency.custom.sort((a, b) => b.period - a.period)[0].period;
+  }
+
+  /**
+   * cleanupImpressions - this function cleans up obsolete impressions whenever
+   * messages are refreshed or fetched. It will likely need to be more sophisticated in the future,
+   * but the current behaviour for when both message impressions and provider impressions are
+   * cleared is as follows (where `item` is either `message` or `provider`):
+   *
+   * 1. If the item id for a list of item impressions no longer exists in the ASRouter state, it
+   *    will be cleared.
+   * 2. If the item has time-bound frequency caps but no lifetime cap, any item impressions older
+   *    than the longest time period will be cleared.
+   */
+  cleanupImpressions() {
+    return this.setState(state => {
+      const messageImpressions = this._cleanupImpressionsForItems(
+        state,
+        state.messages,
+        "messageImpressions"
+      );
+      const groupImpressions = this._cleanupImpressionsForItems(
+        state,
+        state.groups,
+        "groupImpressions"
+      );
+      return { messageImpressions, groupImpressions };
+    });
+  }
+
+  /** _cleanupImpressionsForItems - Helper for cleanupImpressions - calculate the updated
+  /*                                impressions object for the given items, then store it and return it
+   *
+   * @param {obj} state Reference to ASRouter internal state
+   * @param {array} items Can be messages, providers or groups that we count impressions for
+   * @param {string} impressionsString Key name for entry in state where impressions are stored
+   */
+  _cleanupImpressionsForItems(state, items, impressionsString) {
+    const impressions = { ...state[impressionsString] };
+    let needsUpdate = false;
+    Object.keys(impressions).forEach(id => {
+      const [item] = items.filter(x => x.id === id);
+      // Don't keep impressions for items that no longer exist
+      if (!item || !item.frequency || !Array.isArray(impressions[id])) {
+        lazy.ASRouterPreferences.console.debug(
+          "_cleanupImpressionsForItem: removing impressions for deleted or changed item: ",
+          item
+        );
+        lazy.ASRouterPreferences.console.trace();
+        delete impressions[id];
+        needsUpdate = true;
+        return;
+      }
+      if (!impressions[id].length) {
+        return;
+      }
+      // If we don't want to store impressions older than the longest period
+      if (item.frequency.custom && !item.frequency.lifetime) {
+        lazy.ASRouterPreferences.console.debug(
+          "_cleanupImpressionsForItem: removing impressions older than longest period for item: ",
+          item
+        );
+        const now = Date.now();
+        impressions[id] = impressions[id].filter(
+          t => now - t < this.getLongestPeriod(item)
+        );
+        needsUpdate = true;
+      }
+    });
+    if (needsUpdate) {
+      this._storage.set(impressionsString, impressions);
+    }
+    return impressions;
+  }
+
+  handleMessageRequest({
+    messages: candidates,
+    triggerId,
+    triggerParam,
+    triggerContext,
+    template,
+    provider,
+    ordered = false,
+    returnAll = false,
+  }) {
+    let shouldCache;
+    lazy.ASRouterPreferences.console.debug(
+      "in handleMessageRequest, arguments = ",
+      Array.from(arguments) // eslint-disable-line prefer-rest-params
+    );
+    lazy.ASRouterPreferences.console.trace();
+    const messages =
+      candidates ||
+      this.state.messages.filter(m => {
+        if (provider && m.provider !== provider) {
+          lazy.ASRouterPreferences.console.debug(m.id, " filtered by provider");
+          return false;
+        }
+        if (template && m.template !== template) {
+          lazy.ASRouterPreferences.console.debug(m.id, " filtered by template");
+          return false;
+        }
+        if (triggerId && !m.trigger) {
+          lazy.ASRouterPreferences.console.debug(m.id, " filtered by trigger");
+          return false;
+        }
+        if (triggerId && m.trigger.id !== triggerId) {
+          lazy.ASRouterPreferences.console.debug(
+            m.id,
+            " filtered by triggerId"
+          );
+          return false;
+        }
+        if (!this.isUnblockedMessage(m)) {
+          lazy.ASRouterPreferences.console.debug(
+            m.id,
+            " filtered because blocked"
+          );
+          return false;
+        }
+        if (!this.isBelowFrequencyCaps(m)) {
+          lazy.ASRouterPreferences.console.debug(
+            m.id,
+            " filtered because capped"
+          );
+          return false;
+        }
+
+        if (shouldCache !== false) {
+          shouldCache = JEXL_PROVIDER_CACHE.has(m.provider);
+        }
+
+        return true;
+      });
+
+    if (!messages.length) {
+      return returnAll ? messages : null;
+    }
+
+    const context = this._getMessagesContext();
+
+    // Find a message that matches the targeting context as well as the trigger context (if one is provided)
+    // If no trigger is provided, we should find a message WITHOUT a trigger property defined.
+    return lazy.ASRouterTargeting.findMatchingMessage({
+      messages,
+      trigger: triggerId && {
+        id: triggerId,
+        param: triggerParam,
+        context: triggerContext,
+      },
+      context,
+      onError: this._handleTargetingError,
+      ordered,
+      shouldCache,
+      returnAll,
+    });
+  }
+
+  setMessageById({ id, ...data }, force, browser) {
+    return this.routeCFRMessage(this.getMessageById(id), browser, data, force);
+  }
+
+  blockMessageById(idOrIds) {
+    lazy.ASRouterPreferences.console.debug(
+      "blockMessageById called, idOrIds = ",
+      idOrIds
+    );
+    lazy.ASRouterPreferences.console.trace();
+
+    const idsToBlock = Array.isArray(idOrIds) ? idOrIds : [idOrIds];
+
+    return this.setState(state => {
+      const messageBlockList = [...state.messageBlockList];
+      const messageImpressions = { ...state.messageImpressions };
+
+      idsToBlock.forEach(id => {
+        const message = state.messages.find(m => m.id === id);
+        const idToBlock = message && message.campaign ? message.campaign : id;
+        if (!messageBlockList.includes(idToBlock)) {
+          messageBlockList.push(idToBlock);
+        }
+
+        // When a message is blocked, its impressions should be cleared as well
+        delete messageImpressions[id];
+      });
+
+      this._storage.set("messageBlockList", messageBlockList);
+      this._storage.set("messageImpressions", messageImpressions);
+      return { messageBlockList, messageImpressions };
+    });
+  }
+
+  unblockMessageById(idOrIds) {
+    const idsToUnblock = Array.isArray(idOrIds) ? idOrIds : [idOrIds];
+
+    return this.setState(state => {
+      const messageBlockList = [...state.messageBlockList];
+      idsToUnblock
+        .map(id => state.messages.find(m => m.id === id))
+        // Remove all `id`s (or `campaign`s for snippets) from the message
+        // block list
+        .forEach(message => {
+          const idToUnblock =
+            message && message.campaign ? message.campaign : message.id;
+          messageBlockList.splice(messageBlockList.indexOf(idToUnblock), 1);
+        });
+
+      this._storage.set("messageBlockList", messageBlockList);
+      return { messageBlockList };
+    });
+  }
+
+  resetGroupsState() {
+    const newGroupImpressions = {};
+    for (let { id } of this.state.groups) {
+      newGroupImpressions[id] = [];
+    }
+    // Update storage
+    this._storage.set("groupImpressions", newGroupImpressions);
+    return this.setState(({ groups }) => ({
+      groupImpressions: newGroupImpressions,
+    }));
+  }
+
+  resetMessageState() {
+    const newMessageImpressions = {};
+    for (let { id } of this.state.messages) {
+      newMessageImpressions[id] = [];
+    }
+    // Update storage
+    this._storage.set("messageImpressions", newMessageImpressions);
+    return this.setState(() => ({
+      messageImpressions: newMessageImpressions,
+    }));
+  }
+
+  _validPreviewEndpoint(url) {
+    try {
+      const endpoint = new URL(url);
+      if (!this.ALLOWLIST_HOSTS[endpoint.host]) {
+        console.error(
+          `The preview URL host ${endpoint.host} is not in the list of allowed hosts.`
+        );
+      }
+      if (endpoint.protocol !== "https:") {
+        console.error("The URL protocol is not https.");
+      }
+      return (
+        endpoint.protocol === "https:" && this.ALLOWLIST_HOSTS[endpoint.host]
+      );
+    } catch (e) {
+      return false;
+    }
+  }
+
+  // Ensure we switch to the Onboarding message after RTAMO addon was installed
+  _updateOnboardingState() {
+    let addonInstallObs = (subject, topic) => {
+      Services.obs.removeObserver(
+        addonInstallObs,
+        "webextension-install-notify"
+      );
+    };
+    Services.obs.addObserver(addonInstallObs, "webextension-install-notify");
+  }
+
+  _loadSnippetsAllowHosts() {
+    let additionalHosts = [];
+    const allowPrefValue = Services.prefs.getStringPref(
+      SNIPPETS_ENDPOINT_ALLOWLIST,
+      ""
+    );
+    try {
+      additionalHosts = JSON.parse(allowPrefValue);
+    } catch (e) {
+      if (allowPrefValue) {
+        console.error(
+          `Pref ${SNIPPETS_ENDPOINT_ALLOWLIST} value is not valid JSON`
+        );
+      }
+    }
+
+    if (!additionalHosts.length) {
+      return DEFAULT_ALLOWLIST_HOSTS;
+    }
+
+    // If there are additional hosts we want to allow, add them as
+    // `preview` so that the updateCycle is 0
+    return additionalHosts.reduce(
+      (allow_hosts, host) => {
+        allow_hosts[host] = "preview";
+        Services.console.logStringMessage(
+          `Adding ${host} to list of allowed hosts.`
+        );
+        return allow_hosts;
+      },
+      { ...DEFAULT_ALLOWLIST_HOSTS }
+    );
+  }
+
+  // To be passed to ASRouterTriggerListeners
+  _triggerHandler(browser, trigger) {
+    // Disable ASRouterTriggerListeners in kiosk mode.
+    if (lazy.BrowserHandler.kiosk) {
+      return Promise.resolve();
+    }
+    return this.sendTriggerMessage({ ...trigger, browser });
+  }
+
+  _removePreviewEndpoint(state) {
+    state.providers = state.providers.filter(p => p.id !== "preview");
+    return state;
+  }
+
+  addPreviewEndpoint(url, browser) {
+    const providers = [...this.state.providers];
+    if (
+      this._validPreviewEndpoint(url) &&
+      !providers.find(p => p.url === url)
+    ) {
+      // When you view a preview snippet we want to hide all real content -
+      // sending EnterSnippetsPreviewMode puts this browser tab in that state.
+      browser.sendMessageToActor("EnterSnippetsPreviewMode", {}, "ASRouter");
+      providers.push({
+        id: "preview",
+        type: "remote",
+        enabled: true,
+        url,
+        updateCycleInMs: 0,
+      });
+      return this.setState({ providers });
+    }
+    return Promise.resolve();
+  }
+
+  /**
+   * forceAttribution - this function should only be called from within about:newtab#asrouter.
+   * It forces the browser attribution to be set to something specified in asrouter admin
+   * tools, and reloads the providers in order to get messages that are dependant on this
+   * attribution data (see Return to AMO flow in bug 1475354 for example). Note - OSX and Windows only
+   * @param {data} Object an object containing the attribtion data that came from asrouter admin page
+   */
+  async forceAttribution(data) {
+    // Extract the parameters from data that will make up the referrer url
+    const attributionData = AttributionCode.allowedCodeKeys
+      .map(key => `${key}=${encodeURIComponent(data[key] || "")}`)
+      .join("&");
+    if (AppConstants.platform === "win") {
+      // The whole attribution data is encoded (again) for windows
+      await AttributionCode.writeAttributionFile(
+        encodeURIComponent(attributionData)
+      );
+    } else if (AppConstants.platform === "macosx") {
+      let appPath = lazy.MacAttribution.applicationPath;
+      let attributionSvc = Cc["@mozilla.org/mac-attribution;1"].getService(
+        Ci.nsIMacAttributionService
+      );
+
+      // The attribution data is treated as a url query for mac
+      let referrer = `https://www.mozilla.org/anything/?${attributionData}`;
+
+      // This sets the Attribution to be the referrer
+      attributionSvc.setReferrerUrl(appPath, referrer, true);
+
+      // Delete attribution data file
+      await AttributionCode.deleteFileAsync();
+    }
+
+    // Clear cache call is only possible in a testing environment
+    Services.env.set("XPCSHELL_TEST_PROFILE_DIR", "testing");
+
+    // Clear and refresh Attribution, and then fetch the messages again to update
+    AttributionCode._clearCache();
+    await AttributionCode.getAttrDataAsync();
+    await this._updateMessageProviders();
+    return this.loadMessagesFromAllProviders();
+  }
+
+  async sendPBNewTabMessage({ tabId, hideDefault }) {
+    let message = null;
+    const PromoInfo = {
+      FOCUS: { enabledPref: "browser.promo.focus.enabled" },
+      VPN: { enabledPref: "browser.vpn_promo.enabled" },
+      PIN: { enabledPref: "browser.promo.pin.enabled" },
+    };
+    await this.loadMessagesFromAllProviders();
+
+    // If message has hideDefault property set to true
+    // remove from state all pb_newtab messages with type default
+    if (hideDefault) {
+      await this.setState(state => ({
+        messages: state.messages.filter(
+          m => !(m.template === "pb_newtab" && m.type === "default")
+        ),
+      }));
+    }
+
+    // Remove from state pb_newtab messages with PromoType disabled
+    await this.setState(state => ({
+      messages: state.messages.filter(
+        m =>
+          !(
+            m.template === "pb_newtab" &&
+            !Services.prefs.getBoolPref(
+              PromoInfo[m.content?.promoType]?.enabledPref,
+              true
+            )
+          )
+      ),
+    }));
+
+    const telemetryObject = { tabId };
+    TelemetryStopwatch.start("MS_MESSAGE_REQUEST_TIME_MS", telemetryObject);
+    message = await this.handleMessageRequest({
+      template: "pb_newtab",
+    });
+    TelemetryStopwatch.finish("MS_MESSAGE_REQUEST_TIME_MS", telemetryObject);
+
+    // Format urls if any are defined
+    ["infoLinkUrl"].forEach(key => {
+      if (message?.content?.[key]) {
+        message.content[key] = Services.urlFormatter.formatURL(
+          message.content[key]
+        );
+      }
+    });
+
+    return { message };
+  }
+
+  async sendNewTabMessage({ endpoint, tabId, browser }) {
+    let message;
+
+    // Load preview endpoint for snippets if one is sent
+    if (endpoint) {
+      await this.addPreviewEndpoint(endpoint.url, browser);
+    }
+
+    // Load all messages
+    await this.loadMessagesFromAllProviders();
+
+    if (endpoint) {
+      message = await this.handleMessageRequest({ provider: "preview" });
+
+      // We don't want to cache preview messages, remove them after we selected the message to show
+      if (message) {
+        await this.setState(state => ({
+          messages: state.messages.filter(m => m.id !== message.id),
+        }));
+      }
+    } else {
+      const telemetryObject = { tabId };
+      TelemetryStopwatch.start("MS_MESSAGE_REQUEST_TIME_MS", telemetryObject);
+      message = await this.handleMessageRequest({ provider: "snippets" });
+      TelemetryStopwatch.finish("MS_MESSAGE_REQUEST_TIME_MS", telemetryObject);
+    }
+
+    return this.routeCFRMessage(message, browser, undefined, false);
+  }
+
+  _recordReachEvent(message) {
+    const messageGroup = message.forReachEvent.group;
+    // Events telemetry only accepts understores for the event `object`
+    const underscored = messageGroup.split("-").join("_");
+    const extra = { branches: message.branchSlug };
+    Services.telemetry.recordEvent(
+      REACH_EVENT_CATEGORY,
+      REACH_EVENT_METHOD,
+      underscored,
+      message.experimentSlug,
+      extra
+    );
+  }
+
+  async sendTriggerMessage({ tabId, browser, ...trigger }) {
+    await this.loadMessagesFromAllProviders();
+
+    const telemetryObject = { tabId };
+    TelemetryStopwatch.start("MS_MESSAGE_REQUEST_TIME_MS", telemetryObject);
+    // Return all the messages so that it can record the Reach event
+    const messages =
+      (await this.handleMessageRequest({
+        triggerId: trigger.id,
+        triggerParam: trigger.param,
+        triggerContext: trigger.context,
+        returnAll: true,
+      })) || [];
+    TelemetryStopwatch.finish("MS_MESSAGE_REQUEST_TIME_MS", telemetryObject);
+
+    // Record the Reach event for all the messages with `forReachEvent`,
+    // only send the first message without forReachEvent to the target
+    const nonReachMessages = [];
+    for (const message of messages) {
+      if (message.forReachEvent) {
+        if (!message.forReachEvent.sent) {
+          this._recordReachEvent(message);
+          message.forReachEvent.sent = true;
+        }
+      } else {
+        nonReachMessages.push(message);
+      }
+    }
+
+    if (nonReachMessages.length) {
+      let featureId = nonReachMessages[0]._nimbusFeature;
+      if (featureId) {
+        lazy.NimbusFeatures[featureId].recordExposureEvent({ once: true });
+      }
+    }
+
+    return this.routeCFRMessage(
+      nonReachMessages[0] || null,
+      browser,
+      trigger,
+      false
+    );
+  }
+
+  async forceWNPanel(browser) {
+    let win = browser.ownerGlobal;
+    await lazy.ToolbarPanelHub.enableToolbarButton();
+
+    win.PanelUI.showSubView(
+      "PanelUI-whatsNew",
+      win.document.getElementById("whats-new-menu-button")
+    );
+
+    let panel = win.document.getElementById("customizationui-widget-panel");
+    // Set the attribute to keep the panel open
+    panel.setAttribute("noautohide", true);
+  }
+
+  async closeWNPanel(browser) {
+    let win = browser.ownerGlobal;
+    let panel = win.document.getElementById("customizationui-widget-panel");
+    // Set the attribute to allow the panel to close
+    panel.setAttribute("noautohide", false);
+    // Removing the button is enough to close the panel.
+    await lazy.ToolbarPanelHub._hideToolbarButton(win);
+  }
+
+  async _onExperimentForceEnrolled(subject, topic, slug) {
+    const experimentProvider = this.state.providers.find(
+      p => p.id === "messaging-experiments"
+    );
+    if (!experimentProvider.enabled) {
+      return;
+    }
+
+    const branch = lazy.ExperimentAPI.getActiveBranch({ slug });
+    const features = branch.features ?? [branch.feature];
+    const featureIds = features.map(feature => feature.featureId);
+
+    this._onFeaturesUpdated(...featureIds);
+
+    await this.loadMessagesFromAllProviders([experimentProvider]);
+  }
+
+  /**
+   * Handle a change to the list of featureIds that the messaging-experiments
+   * provider is watching.
+   *
+   * This normally occurs when ASRouter update message providers, which happens
+   * every startup and when the messaging-experiment provider pref changes.
+   *
+   * On startup, |oldFeatures| will be an empty array and we will subscribe to
+   * everything in |newFeatures|.
+   *
+   * When the pref changes, we unsubscribe from |oldFeatures - newFeatures| and
+   * subscribe to |newFeatures - oldFeatures|. Features that are listed in both
+   * sets do not have their subscription status changed. Pref changes are mostly
+   * during unit tests.
+   *
+   * @param {string[]} oldFeatures The list of feature IDs we were previously
+   *                               listening to for new experiments.
+   * @param {string[]} newFeatures The list of feature IDs we are now listening
+   *                               to for new experiments.
+   */
+  _onFeatureListChanged(oldFeatures, newFeatures) {
+    for (const featureId of oldFeatures) {
+      if (!newFeatures.includes(featureId)) {
+        const listener = this._experimentChangedListeners.get(featureId);
+        this._experimentChangedListeners.delete(featureId);
+        lazy.NimbusFeatures[featureId].off(listener);
+      }
+    }
+
+    const newlySubscribed = [];
+
+    for (const featureId of newFeatures) {
+      if (!oldFeatures.includes(featureId)) {
+        const listener = () => this._onFeaturesUpdated(featureId);
+        this._experimentChangedListeners.set(featureId, listener);
+        lazy.NimbusFeatures[featureId].onUpdate(listener);
+
+        newlySubscribed.push(featureId);
+      }
+    }
+
+    // Check for any messages present in the newly subscribed to Nimbus features
+    // so we can prefetch their remote images (if any).
+    this._onFeaturesUpdated(...newlySubscribed);
+  }
+
+  /**
+   * Handle updated experiment features.
+   *
+   * If there are messages for the feature, RemoteImages will prefetch any
+   * images.
+   *
+   * @param {string[]} featureIds The feature IDs that have been updated.
+   */
+  _onFeaturesUpdated(...featureIds) {
+    const messages = [];
+
+    for (const featureId of featureIds) {
+      const featureAPI = lazy.NimbusFeatures[featureId];
+      // If there is no active experiment for the feature, this will return
+      // null.
+      if (lazy.ExperimentAPI.getExperimentMetaData({ featureId })) {
+        // Otherwise, getAllVariables() will return the JSON blob for the
+        // message.
+        messages.push(featureAPI.getAllVariables());
+      }
+    }
+
+    // We are not awaiting this because we want these images to load in the
+    // background.
+    if (messages.length) {
+      lazy.RemoteImages.prefetchImagesFor(messages);
+    }
+  }
+
+  async forcePBWindow(browser, msg) {
+    const privateBrowserOpener = await new Promise((
+      resolveOnContentBrowserCreated // wrap this in a promise to give back the right browser
+    ) =>
+      browser.ownerGlobal.openTrustedLinkIn(
+        "about:privatebrowsing?debug",
+        "window",
+        {
+          private: true,
+          triggeringPrincipal: Services.scriptSecurityManager.getSystemPrincipal(
+            {}
+          ),
+          csp: null,
+          resolveOnContentBrowserCreated,
+          opener: "devtools",
+        }
+      )
+    );
+
+    lazy.setTimeout(() => {
+      // setTimeout is necessary to make sure the private browsing window has a chance to open before the message is sent
+      privateBrowserOpener.browsingContext.currentWindowGlobal
+        .getActor("AboutPrivateBrowsing")
+        .sendAsyncMessage("ShowDevToolsMessage", msg);
+    }, 100);
+
+    return privateBrowserOpener;
+  }
+}
+
+/**
+ * ASRouter - singleton instance of _ASRouter that controls all messages
+ * in the new tab page.
+ */
+const ASRouter = new _ASRouter();
+
+const EXPORTED_SYMBOLS = ["_ASRouter", "ASRouter", "MessageLoaderUtils"];