alled once per
    // query but cancelQuery can be called multiple times per query.
    // The frequent cancels can cause the extension's state to drift from the
    // provider's state.
    if (lazy.ExtensionSearchHandler.hasActiveInputSession()) {
      lazy.ExtensionSearchHandler.handleInputCancelled();
    }

    return false;
  }

  /**
   * Gets the provider's priority.
   *
   * @returns {number}
   *   The provider's priority for the given query.
   */
  getPriority() {
    return 0;
  }

  /**
   * Starts querying.
   *
   * @param {UrlbarQueryContext} queryContext
   * @param {(provider: UrlbarProvider, result: UrlbarResult) => void} addCallback
   *   Callback invoked by the provider to add a new result.
   */
  async startQuery(queryContext, addCallback) {
    let instance = this.queryInstance;

    // Fetch heuristic result.
    let keyword = queryContext.tokens[0].value;
    let description = lazy.ExtensionSearchHandler.getDescription(keyword);
    let heuristicResult = new lazy.UrlbarResult({
      type: UrlbarUtils.RESULT_TYPE.OMNIBOX,
      source: UrlbarUtils.RESULT_SOURCE.ADDON,
      heuristic: true,
      payload: {
        title: description,
        content: queryContext.searchString,
        keyword: queryContext.tokens[0].value,
        icon: UrlbarUtils.ICON.EXTENSION,
      },
      highlights: {
        title: UrlbarUtils.HIGHLIGHT.TYPED,
        content: UrlbarUtils.HIGHLIGHT.TYPED,
        keyword: UrlbarUtils.HIGHLIGHT.TYPED,
      },
    });
    addCallback(this, heuristicResult);

    // Fetch non-heuristic results.
    let data = {
      keyword,
      text: queryContext.searchString,
      inPrivateWindow: queryContext.isPrivate,
    };
    let resultsPromise = lazy.ExtensionSearchHandler.handleSearch(
      data,
      suggestions => {
        if (instance != this.queryInstance) {
          return;
        }
        for (let suggestion of suggestions) {
          let content = `${queryContext.tokens[0].value} ${suggestion.content}`;
          if (content == heuristicResult.payload.content) {
            continue;
          }
          let result = new lazy.UrlbarResult({
            type: UrlbarUtils.RESULT_TYPE.OMNIBOX,
            source: UrlbarUtils.RESULT_SOURCE.ADDON,
            payload: {
              title: suggestion.description,
              content,
              keyword: queryContext.tokens[0].value,
              isBlockable: suggestion.deletable,
              icon: UrlbarUtils.ICON.EXTENSION,
            },
            highlights: {
              title: UrlbarUtils.HIGHLIGHT.TYPED,
              content: UrlbarUtils.HIGHLIGHT.TYPED,
              keyword: UrlbarUtils.HIGHLIGHT.TYPED,
            },
          });
          addCallback(this, result);
        }
      }
    );

    // Since the extension has no way to signal when it's done pushing results,
    // we add a timer racing with the addition.
    let timeoutPromise = new SkippableTimer({
      name: "ProviderOmnibox",
      time: lazy.UrlbarPrefs.get("extension.omnibox.timeout"),
      logger: this.logger,
    }).promise;
    await Promise.race([timeoutPromise, resultsPromise]).catch(ex =>
      this.logger.error(ex)
    );
  }

  onEngagement(queryContext, controller, details) {
    let { result } = details;
    if (details.selType == "dismiss" && result.payload.isBlockable) {
      lazy.ExtensionSearchHandler.handleInputDeleted(result.payload.title);
      controller.removeResult(result);
    }
  }
}
PK