BB 40069: Add helpers for message passing with extensions

  /** @type {Map<number, Promise>} */

  portPromises: new Map(),

  _torRuntimeMessageListeners: [],

  init() {

    this.conduit = new lazy.BroadcastConduit(ProxyMessenger, {

      id: "ProxyMessenger",

  },

  async recvRuntimeMessage(arg, { sender }) {

    // We need to listen to some extension messages in Tor Browser

    for (const listener of this._torRuntimeMessageListeners) {

      listener(arg);

    }

    arg.firstResponse = true;

    let kind = await this.normalizeArgs(arg, sender);

    arg.query = true;

Services.obs.addObserver(StartupCache, "startupcache-invalidate");

async function torSendExtensionMessage(extensionId, message) {

  // This should broadcast the message to all children "conduits"

  // listening for a "RuntimeMessage". Those children conduits

  // will either be extension background pages or other extension

  // pages listening to browser.runtime.onMessage.

  const result = await ProxyMessenger.conduit.castRuntimeMessage("messenger", {

    extensionId,

    holder: new StructuredCloneHolder("torSendExtensionMessage", null, message),

    query: true,

    firstResponse: true,

    sender: {

      id: extensionId,

      envType: "addon_child",

    },

  });

  return result

    ? result.value

    : Promise.reject({ message: ERROR_NO_RECEIVERS });

}

async function torWaitForExtensionMessage(extensionId, checker) {

  return new Promise(resolve => {

    const msgListener = msg => {

      try {

        if (msg && msg.extensionId === extensionId) {

          const deserialized = msg.holder.deserialize({});

          if (checker(deserialized)) {

            const idx =

              ProxyMessenger._torRuntimeMessageListeners.indexOf(msgListener);

            ProxyMessenger._torRuntimeMessageListeners.splice(idx, 1);

            resolve(deserialized);

          }

        }

      } catch (e) {}

    };

    ProxyMessenger._torRuntimeMessageListeners.push(msgListener);

  });

}

export var ExtensionParent = {

  GlobalManager,

  HiddenExtensionPage,

  watchExtensionProxyContextLoad,

  watchExtensionWorkerContextLoaded,

  DebugUtils,

  torSendExtensionMessage,

  torWaitForExtensionMessage,

};

// browserPaintedPromise and browserStartupPromise are promises that