Adding upstream version 86.0.1.upstream/86.0.1upstream

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

1 files changed, 899 insertions, 0 deletions

diff --git a/browser/components/urlbar/UrlbarController.jsm b/browser/components/urlbar/UrlbarController.jsm
new file mode 100644
index 0000000000..15aad7c48b
--- /dev/null
+++ b/browser/components/urlbar/UrlbarController.jsm
@@ -0,0 +1,899 @@
+/* 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";
+
+var EXPORTED_SYMBOLS = ["UrlbarController"];
+
+const { XPCOMUtils } = ChromeUtils.import(
+  "resource://gre/modules/XPCOMUtils.jsm"
+);
+const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
+XPCOMUtils.defineLazyModuleGetters(this, {
+  AppConstants: "resource://gre/modules/AppConstants.jsm",
+  BrowserSearchTelemetry: "resource:///modules/BrowserSearchTelemetry.jsm",
+  FormHistory: "resource://gre/modules/FormHistory.jsm",
+  PlacesUtils: "resource://gre/modules/PlacesUtils.jsm",
+  UrlbarPrefs: "resource:///modules/UrlbarPrefs.jsm",
+  UrlbarProvidersManager: "resource:///modules/UrlbarProvidersManager.jsm",
+  UrlbarTokenizer: "resource:///modules/UrlbarTokenizer.jsm",
+  UrlbarUtils: "resource:///modules/UrlbarUtils.jsm",
+});
+
+const TELEMETRY_1ST_RESULT = "PLACES_AUTOCOMPLETE_1ST_RESULT_TIME_MS";
+const TELEMETRY_6_FIRST_RESULTS = "PLACES_AUTOCOMPLETE_6_FIRST_RESULTS_TIME_MS";
+const NOTIFICATIONS = {
+  QUERY_STARTED: "onQueryStarted",
+  QUERY_RESULTS: "onQueryResults",
+  QUERY_RESULT_REMOVED: "onQueryResultRemoved",
+  QUERY_CANCELLED: "onQueryCancelled",
+  QUERY_FINISHED: "onQueryFinished",
+  VIEW_OPEN: "onViewOpen",
+  VIEW_CLOSE: "onViewClose",
+};
+
+/**
+ * The address bar controller handles queries from the address bar, obtains
+ * results and returns them to the UI for display.
+ *
+ * Listeners may be added to listen for the results. They may support the
+ * following methods which may be called when a query is run:
+ *
+ * - onQueryStarted(queryContext)
+ * - onQueryResults(queryContext)
+ * - onQueryCancelled(queryContext)
+ * - onQueryFinished(queryContext)
+ * - onQueryResultRemoved(index)
+ * - onViewOpen()
+ * - onViewClose()
+ */
+class UrlbarController {
+  /**
+   * Initialises the class. The manager may be overridden here, this is for
+   * test purposes.
+   *
+   * @param {object} options
+   *   The initial options for UrlbarController.
+   * @param {UrlbarInput} options.input
+   *   The input this controller is operating with.
+   * @param {object} [options.manager]
+   *   Optional fake providers manager to override the built-in providers manager.
+   *   Intended for use in unit tests only.
+   */
+  constructor(options = {}) {
+    if (!options.input) {
+      throw new Error("Missing options: input");
+    }
+    if (!options.input.window) {
+      throw new Error("input is missing 'window' property.");
+    }
+    if (
+      !options.input.window.location ||
+      options.input.window.location.href != AppConstants.BROWSER_CHROME_URL
+    ) {
+      throw new Error("input.window should be an actual browser window.");
+    }
+    if (!("isPrivate" in options.input)) {
+      throw new Error("input.isPrivate must be set.");
+    }
+
+    this.input = options.input;
+    this.browserWindow = options.input.window;
+
+    this.manager = options.manager || UrlbarProvidersManager;
+
+    this._listeners = new Set();
+    this._userSelectionBehavior = "none";
+
+    this.engagementEvent = new TelemetryEvent(
+      this,
+      options.eventTelemetryCategory
+    );
+  }
+
+  get NOTIFICATIONS() {
+    return NOTIFICATIONS;
+  }
+
+  /**
+   * Hooks up the controller with a view.
+   *
+   * @param {UrlbarView} view
+   *   The UrlbarView instance associated with this controller.
+   */
+  setView(view) {
+    this.view = view;
+  }
+
+  /**
+   * Takes a query context and starts the query based on the user input.
+   *
+   * @param {UrlbarQueryContext} queryContext The query details.
+   */
+  async startQuery(queryContext) {
+    // Cancel any running query.
+    this.cancelQuery();
+
+    // Wrap the external queryContext, to track a unique object, in case
+    // the external consumer reuses the same context multiple times.
+    // This also allows to add properties without polluting the context.
+    // Note this can't be null-ed or deleted once a query is done, because it's
+    // used by handleDeleteEntry and handleKeyNavigation, that can run after
+    // a query is cancelled or finished.
+    let contextWrapper = (this._lastQueryContextWrapper = { queryContext });
+
+    queryContext.lastResultCount = 0;
+    TelemetryStopwatch.start(TELEMETRY_1ST_RESULT, queryContext);
+    TelemetryStopwatch.start(TELEMETRY_6_FIRST_RESULTS, queryContext);
+
+    // For proper functionality we must ensure this notification is fired
+    // synchronously, as soon as startQuery is invoked, but after any
+    // notifications related to the previous query.
+    this.notify(NOTIFICATIONS.QUERY_STARTED, queryContext);
+    await this.manager.startQuery(queryContext, this);
+    // If the query has been cancelled, onQueryFinished was notified already.
+    // Note this._lastQueryContextWrapper may have changed in the meanwhile.
+    if (
+      contextWrapper === this._lastQueryContextWrapper &&
+      !contextWrapper.done
+    ) {
+      contextWrapper.done = true;
+      // TODO (Bug 1549936) this is necessary to avoid leaks in PB tests.
+      this.manager.cancelQuery(queryContext);
+      this.notify(NOTIFICATIONS.QUERY_FINISHED, queryContext);
+    }
+    return queryContext;
+  }
+
+  /**
+   * Cancels an in-progress query. Note, queries may continue running if they
+   * can't be cancelled.
+   */
+  cancelQuery() {
+    // If the query finished already, don't handle cancel.
+    if (!this._lastQueryContextWrapper || this._lastQueryContextWrapper.done) {
+      return;
+    }
+
+    this._lastQueryContextWrapper.done = true;
+
+    let { queryContext } = this._lastQueryContextWrapper;
+    TelemetryStopwatch.cancel(TELEMETRY_1ST_RESULT, queryContext);
+    TelemetryStopwatch.cancel(TELEMETRY_6_FIRST_RESULTS, queryContext);
+    this.manager.cancelQuery(queryContext);
+    this.notify(NOTIFICATIONS.QUERY_CANCELLED, queryContext);
+    this.notify(NOTIFICATIONS.QUERY_FINISHED, queryContext);
+  }
+
+  /**
+   * Receives results from a query.
+   *
+   * @param {UrlbarQueryContext} queryContext The query details.
+   */
+  receiveResults(queryContext) {
+    if (queryContext.lastResultCount < 1 && queryContext.results.length >= 1) {
+      TelemetryStopwatch.finish(TELEMETRY_1ST_RESULT, queryContext);
+    }
+    if (queryContext.lastResultCount < 6 && queryContext.results.length >= 6) {
+      TelemetryStopwatch.finish(TELEMETRY_6_FIRST_RESULTS, queryContext);
+    }
+
+    if (queryContext.firstResultChanged) {
+      // Notify the input so it can make adjustments based on the first result.
+      if (this.input.onFirstResult(queryContext.results[0])) {
+        // The input canceled the query and started a new one.
+        return;
+      }
+
+      // The first time we receive results try to connect to the heuristic
+      // result.
+      this.speculativeConnect(
+        queryContext.results[0],
+        queryContext,
+        "resultsadded"
+      );
+    }
+
+    this.notify(NOTIFICATIONS.QUERY_RESULTS, queryContext);
+    // Update lastResultCount after notifying, so the view can use it.
+    queryContext.lastResultCount = queryContext.results.length;
+  }
+
+  /**
+   * Adds a listener for query actions and results.
+   *
+   * @param {object} listener The listener to add.
+   * @throws {TypeError} Throws if the listener is not an object.
+   */
+  addQueryListener(listener) {
+    if (!listener || typeof listener != "object") {
+      throw new TypeError("Expected listener to be an object");
+    }
+    this._listeners.add(listener);
+  }
+
+  /**
+   * Removes a query listener.
+   *
+   * @param {object} listener The listener to add.
+   */
+  removeQueryListener(listener) {
+    this._listeners.delete(listener);
+  }
+
+  /**
+   * Checks whether a keyboard event that would normally open the view should
+   * instead be handled natively by the input field.
+   * On certain platforms, the up and down keys can be used to move the caret,
+   * in which case we only want to open the view if the caret is at the
+   * start or end of the input.
+   *
+   * @param {KeyboardEvent} event
+   *   The DOM KeyboardEvent.
+   * @returns {boolean}
+   *   Returns true if the event should move the caret instead of opening the
+   *   view.
+   */
+  keyEventMovesCaret(event) {
+    if (this.view.isOpen) {
+      return false;
+    }
+    if (AppConstants.platform != "macosx" && AppConstants.platform != "linux") {
+      return false;
+    }
+    let isArrowUp = event.keyCode == KeyEvent.DOM_VK_UP;
+    let isArrowDown = event.keyCode == KeyEvent.DOM_VK_DOWN;
+    if (!isArrowUp && !isArrowDown) {
+      return false;
+    }
+    let start = this.input.selectionStart;
+    let end = this.input.selectionEnd;
+    if (
+      end != start ||
+      (isArrowUp && start > 0) ||
+      (isArrowDown && end < this.input.value.length)
+    ) {
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Receives keyboard events from the input and handles those that should
+   * navigate within the view or pick the currently selected item.
+   *
+   * @param {KeyboardEvent} event
+   *   The DOM KeyboardEvent.
+   * @param {boolean} executeAction
+   *   Whether the event should actually execute the associated action, or just
+   *   be managed (at a preventDefault() level). This is used when the event
+   *   will be deferred by the event bufferer, but preventDefault() and friends
+   *   should still happen synchronously.
+   */
+  handleKeyNavigation(event, executeAction = true) {
+    const isMac = AppConstants.platform == "macosx";
+    // Handle readline/emacs-style navigation bindings on Mac.
+    if (
+      isMac &&
+      this.view.isOpen &&
+      event.ctrlKey &&
+      (event.key == "n" || event.key == "p")
+    ) {
+      if (executeAction) {
+        this.view.selectBy(1, { reverse: event.key == "p" });
+      }
+      event.preventDefault();
+      return;
+    }
+
+    if (this.view.isOpen && executeAction && this._lastQueryContextWrapper) {
+      let { queryContext } = this._lastQueryContextWrapper;
+      let handled = this.view.oneOffSearchButtons.handleKeyDown(
+        event,
+        this.view.visibleElementCount,
+        this.view.allowEmptySelection,
+        queryContext.searchString
+      );
+      if (handled) {
+        return;
+      }
+    }
+
+    switch (event.keyCode) {
+      case KeyEvent.DOM_VK_ESCAPE:
+        if (executeAction) {
+          if (this.view.isOpen) {
+            this.view.close();
+          } else {
+            this.input.handleRevert();
+          }
+        }
+        event.preventDefault();
+        break;
+      case KeyEvent.DOM_VK_RETURN:
+        if (executeAction) {
+          this.input.handleCommand(event);
+        }
+        event.preventDefault();
+        break;
+      case KeyEvent.DOM_VK_TAB:
+        // It's always possible to tab through results when the urlbar was
+        // focused with the mouse, or has a search string.
+        // We allow tabbing without a search string when in search mode preview,
+        // since that means the user has interacted with the Urlbar since
+        // opening it.
+        // When there's no search string, we want to focus the next toolbar item
+        // instead, for accessibility reasons.
+        let allowTabbingThroughResults =
+          this.input.focusedViaMousedown ||
+          this.input.searchMode?.isPreview ||
+          (this.input.value &&
+            this.input.getAttribute("pageproxystate") != "valid");
+        if (
+          // Even if the view is closed, we may be waiting results, and in
+          // such a case we don't want to tab out of the urlbar.
+          (this.view.isOpen || !executeAction) &&
+          !event.ctrlKey &&
+          !event.altKey &&
+          allowTabbingThroughResults
+        ) {
+          if (executeAction) {
+            this.userSelectionBehavior = "tab";
+            this.view.selectBy(1, {
+              reverse: event.shiftKey,
+              userPressedTab: true,
+            });
+          }
+          event.preventDefault();
+        }
+        break;
+      case KeyEvent.DOM_VK_DOWN:
+      case KeyEvent.DOM_VK_UP:
+      case KeyEvent.DOM_VK_PAGE_DOWN:
+      case KeyEvent.DOM_VK_PAGE_UP:
+        if (event.ctrlKey || event.altKey) {
+          break;
+        }
+        if (this.view.isOpen) {
+          if (executeAction) {
+            this.userSelectionBehavior = "arrow";
+            this.view.selectBy(
+              event.keyCode == KeyEvent.DOM_VK_PAGE_DOWN ||
+                event.keyCode == KeyEvent.DOM_VK_PAGE_UP
+                ? UrlbarUtils.PAGE_UP_DOWN_DELTA
+                : 1,
+              {
+                reverse:
+                  event.keyCode == KeyEvent.DOM_VK_UP ||
+                  event.keyCode == KeyEvent.DOM_VK_PAGE_UP,
+              }
+            );
+          }
+        } else {
+          if (this.keyEventMovesCaret(event)) {
+            break;
+          }
+          if (executeAction) {
+            this.userSelectionBehavior = "arrow";
+            this.input.startQuery({
+              searchString: this.input.value,
+              event,
+            });
+          }
+        }
+        event.preventDefault();
+        break;
+      case KeyEvent.DOM_VK_RIGHT:
+      case KeyEvent.DOM_VK_END:
+        this.input.maybeConfirmSearchModeFromResult({
+          entry: "typed",
+        });
+      // Fall through.
+      case KeyEvent.DOM_VK_LEFT:
+      case KeyEvent.DOM_VK_HOME:
+        this.view.removeAccessibleFocus();
+        break;
+      case KeyEvent.DOM_VK_BACK_SPACE:
+        if (
+          this.input.searchMode &&
+          this.input.selectionStart == 0 &&
+          this.input.selectionEnd == 0 &&
+          !event.shiftKey
+        ) {
+          this.input.searchMode = null;
+          this.input.view.oneOffSearchButtons.selectedButton = null;
+          this.input.startQuery({
+            allowAutofill: false,
+            event,
+          });
+        }
+      // Fall through.
+      case KeyEvent.DOM_VK_DELETE:
+        if (!this.view.isOpen) {
+          break;
+        }
+        if (event.shiftKey) {
+          if (!executeAction || this._handleDeleteEntry()) {
+            event.preventDefault();
+          }
+        } else if (executeAction) {
+          this.userSelectionBehavior = "none";
+        }
+        break;
+    }
+  }
+
+  /**
+   * Tries to initialize a speculative connection on a result.
+   * Speculative connections are only supported for a subset of all the results.
+   * @param {UrlbarResult} result Tthe result to speculative connect to.
+   * @param {UrlbarQueryContext} context The queryContext
+   * @param {string} reason Reason for the speculative connect request.
+   * @note speculative connect to:
+   *  - Search engine heuristic results
+   *  - autofill results
+   *  - http/https results
+   */
+  speculativeConnect(result, context, reason) {
+    // Never speculative connect in private contexts.
+    if (!this.input || context.isPrivate || !context.results.length) {
+      return;
+    }
+    let { url } = UrlbarUtils.getUrlFromResult(result);
+    if (!url) {
+      return;
+    }
+
+    switch (reason) {
+      case "resultsadded": {
+        // We should connect to an heuristic result, if it exists.
+        if (
+          (result == context.results[0] && result.heuristic) ||
+          result.autofill
+        ) {
+          if (result.type == UrlbarUtils.RESULT_TYPE.SEARCH) {
+            // Speculative connect only if search suggestions are enabled.
+            if (
+              UrlbarPrefs.get("suggest.searches") &&
+              UrlbarPrefs.get("browser.search.suggest.enabled")
+            ) {
+              let engine = Services.search.getEngineByName(
+                result.payload.engine
+              );
+              UrlbarUtils.setupSpeculativeConnection(
+                engine,
+                this.browserWindow
+              );
+            }
+          } else if (result.autofill) {
+            UrlbarUtils.setupSpeculativeConnection(url, this.browserWindow);
+          }
+        }
+        return;
+      }
+      case "mousedown": {
+        // On mousedown, connect only to http/https urls.
+        if (url.startsWith("http")) {
+          UrlbarUtils.setupSpeculativeConnection(url, this.browserWindow);
+        }
+        return;
+      }
+      default: {
+        throw new Error("Invalid speculative connection reason");
+      }
+    }
+  }
+
+  /**
+   * Stores the selection behavior that the user has used to select a result.
+   *
+   * @param {"arrow"|"tab"|"none"} behavior
+   *   The behavior the user used.
+   */
+  set userSelectionBehavior(behavior) {
+    // Don't change the behavior to arrow if tab has already been recorded,
+    // as we want to know that the tab was used first.
+    if (behavior == "arrow" && this._userSelectionBehavior == "tab") {
+      return;
+    }
+    this._userSelectionBehavior = behavior;
+  }
+
+  /**
+   * Records details of the selected result in telemetry. We only record the
+   * selection behavior, type and index.
+   *
+   * @param {Event} event
+   *   The event which triggered the result to be selected.
+   * @param {UrlbarResult} result
+   *   The selected result.
+   */
+  recordSelectedResult(event, result) {
+    let resultIndex = result ? result.rowIndex : -1;
+    let selectedResult = -1;
+    if (resultIndex >= 0) {
+      // Except for the history popup, the urlbar always has a selection.  The
+      // first result at index 0 is the "heuristic" result that indicates what
+      // will happen when you press the Enter key.  Treat it as no selection.
+      selectedResult = resultIndex > 0 || !result.heuristic ? resultIndex : -1;
+    }
+    BrowserSearchTelemetry.recordSearchSuggestionSelectionMethod(
+      event,
+      "urlbar",
+      selectedResult,
+      this._userSelectionBehavior
+    );
+
+    if (!result) {
+      return;
+    }
+
+    // Do not modify existing telemetry types.  To add a new type:
+    //
+    // * Set telemetryType appropriately. Since telemetryType is used as the
+    //   probe name, it must be alphanumeric with optional underscores.
+    // * Add a new keyed scalar probe into the urlbar.picked category for the
+    //   newly added telemetryType.
+    // * Add a test named browser_UsageTelemetry_urlbar_newType.js to
+    //   browser/modules/test/browser.
+    //
+    // The "topsite" type overrides the other ones, because it starts from a
+    // unique user interaction, that we want to count apart. We do this here
+    // rather than in telemetryTypeFromResult because other consumers, like
+    // events telemetry, are reporting this information separately.
+    let telemetryType =
+      result.providerName == "UrlbarProviderTopSites"
+        ? "topsite"
+        : UrlbarUtils.telemetryTypeFromResult(result);
+    Services.telemetry.keyedScalarAdd(
+      `urlbar.picked.${telemetryType}`,
+      resultIndex,
+      1
+    );
+    if (this.input.searchMode && !this.input.searchMode.isPreview) {
+      Services.telemetry.keyedScalarAdd(
+        `urlbar.picked.searchmode.${this.input.searchMode.entry}`,
+        resultIndex,
+        1
+      );
+    }
+
+    // These histograms should be removed after a deprecation time where we'll
+    // confirm goodness of the new scalar above.
+    if (!(telemetryType in UrlbarUtils.SELECTED_RESULT_TYPES)) {
+      Cu.reportError(`Unsupported telemetry type ${telemetryType}`);
+      return;
+    }
+    Services.telemetry
+      .getHistogramById("FX_URLBAR_SELECTED_RESULT_INDEX")
+      .add(resultIndex);
+    Services.telemetry
+      .getHistogramById("FX_URLBAR_SELECTED_RESULT_TYPE_2")
+      .add(UrlbarUtils.SELECTED_RESULT_TYPES[telemetryType]);
+    Services.telemetry
+      .getKeyedHistogramById("FX_URLBAR_SELECTED_RESULT_INDEX_BY_TYPE_2")
+      .add(telemetryType, resultIndex);
+  }
+
+  /**
+   * Internal function handling deletion of entries. We only support removing
+   * of history entries - other result sources will be ignored.
+   *
+   * @returns {boolean} Returns true if the deletion was acted upon.
+   */
+  _handleDeleteEntry() {
+    if (!this._lastQueryContextWrapper) {
+      Cu.reportError("Cannot delete - the latest query is not present");
+      return false;
+    }
+
+    const selectedResult = this.input.view.selectedResult;
+    if (
+      !selectedResult ||
+      selectedResult.source != UrlbarUtils.RESULT_SOURCE.HISTORY ||
+      selectedResult.heuristic
+    ) {
+      return false;
+    }
+
+    let { queryContext } = this._lastQueryContextWrapper;
+    let index = queryContext.results.indexOf(selectedResult);
+    if (index < 0) {
+      Cu.reportError("Failed to find the selected result in the results");
+      return false;
+    }
+
+    queryContext.results.splice(index, 1);
+    this.notify(NOTIFICATIONS.QUERY_RESULT_REMOVED, index);
+
+    // Form history or url restyled as search.
+    if (selectedResult.type == UrlbarUtils.RESULT_TYPE.SEARCH) {
+      if (!queryContext.formHistoryName) {
+        return false;
+      }
+      // Generate the search url to remove it from browsing history.
+      let { url } = UrlbarUtils.getUrlFromResult(selectedResult);
+      PlacesUtils.history.remove(url).catch(Cu.reportError);
+      // Now remove form history.
+      FormHistory.update(
+        {
+          op: "remove",
+          fieldname: queryContext.formHistoryName,
+          value: selectedResult.payload.suggestion,
+        },
+        {
+          handleError(error) {
+            Cu.reportError(`Removing form history failed: ${error}`);
+          },
+        }
+      );
+      return true;
+    }
+
+    // Remove browsing history entries from Places.
+    PlacesUtils.history
+      .remove(selectedResult.payload.url)
+      .catch(Cu.reportError);
+    return true;
+  }
+
+  /**
+   * Notifies listeners of results.
+   *
+   * @param {string} name Name of the notification.
+   * @param {object} params Parameters to pass with the notification.
+   */
+  notify(name, ...params) {
+    for (let listener of this._listeners) {
+      // Can't use "in" because some tests proxify these.
+      if (typeof listener[name] != "undefined") {
+        try {
+          listener[name](...params);
+        } catch (ex) {
+          Cu.reportError(ex);
+        }
+      }
+    }
+  }
+}
+
+/**
+ * Tracks and records telemetry events for the given category, if provided,
+ * otherwise it's a no-op.
+ * It is currently designed around the "urlbar" category, even if it can
+ * potentially be extended to other categories.
+ * To record an event, invoke start() with a starting event, then either
+ * invoke record() with a final event, or discard() to drop the recording.
+ * @see Events.yaml
+ */
+class TelemetryEvent {
+  constructor(controller, category) {
+    this._controller = controller;
+    this._category = category;
+    this._isPrivate = controller.input.isPrivate;
+  }
+
+  /**
+   * Start measuring the elapsed time from a user-generated event.
+   * After this has been invoked, any subsequent calls to start() are ignored,
+   * until either record() or discard() are invoked. Thus, it is safe to keep
+   * invoking this on every input event as the user is typing, for example.
+   * @param {event} event A DOM event.
+   * @param {string} [searchString] Pass a search string related to the event if
+   *        you have one.  The event by itself sometimes isn't enough to
+   *        determine the telemetry details we should record.
+   * @note This should never throw, or it may break the urlbar.
+   * @see the in-tree urlbar telemetry documentation.
+   */
+  start(event, searchString = null) {
+    // In case of a "returned" interaction ongoing, the user may either
+    // continue the search, or restart with a new search string. In that case
+    // we want to change the interaction type to "restarted".
+    // Detecting all the possible ways of clearing the input would be tricky,
+    // thus this makes a guess by just checking the first char matches; even if
+    // the user backspaces a part of the string, we still count that as a
+    // "returned" interaction.
+    if (
+      this._startEventInfo &&
+      this._startEventInfo.interactionType == "returned" &&
+      (!searchString || this._startEventInfo.searchString[0] != searchString[0])
+    ) {
+      this._startEventInfo.interactionType = "restarted";
+    }
+
+    // start is invoked on a user-generated event, but we only count the first
+    // one.  Once an engagement or abandoment happens, we clear _startEventInfo.
+    if (!this._category || this._startEventInfo) {
+      return;
+    }
+    if (!event) {
+      Cu.reportError("Must always provide an event");
+      return;
+    }
+    const validEvents = [
+      "click",
+      "command",
+      "drop",
+      "input",
+      "keydown",
+      "mousedown",
+      "tabswitch",
+      "focus",
+    ];
+    if (!validEvents.includes(event.type)) {
+      Cu.reportError("Can't start recording from event type: " + event.type);
+      return;
+    }
+
+    let interactionType = "topsites";
+    if (event.interactionType) {
+      interactionType = event.interactionType;
+    } else if (event.type == "input") {
+      interactionType = UrlbarUtils.isPasteEvent(event) ? "pasted" : "typed";
+    } else if (event.type == "drop") {
+      interactionType = "dropped";
+    } else if (searchString) {
+      interactionType = "typed";
+    }
+
+    this._startEventInfo = {
+      timeStamp: event.timeStamp || Cu.now(),
+      interactionType,
+      searchString,
+    };
+
+    this._controller.manager.notifyEngagementChange(this._isPrivate, "start");
+  }
+
+  /**
+   * Record an engagement telemetry event.
+   * When the user picks a result from a search through the mouse or keyboard,
+   * an engagement event is recorded. If instead the user abandons a search, by
+   * blurring the input field, an abandonment event is recorded.
+   * @param {event} [event] A DOM event.
+   * @param {object} details An object describing action details.
+   * @param {string} details.searchString The user's search string. Note that
+   *        this string is not sent with telemetry data. It is only used
+   *        locally to discern other data, such as the number of characters and
+   *        words in the string.
+   * @param {string} details.selIndex Index of the selected result, undefined
+   *        for "blur".
+   * @param {string} details.selType type of the selected element, undefined
+   *        for "blur". One of "unknown", "autofill", "visiturl", "bookmark",
+   *        "history", "keyword", "searchengine", "searchsuggestion",
+   *        "switchtab", "remotetab", "extension", "oneoff".
+   * @param {string} details.provider The name of the provider for the selected
+   *        result.
+   * @note event can be null, that usually happens for paste&go or drop&go.
+   *       If there's no _startEventInfo this is a no-op.
+   */
+  record(event, details) {
+    // This should never throw, or it may break the urlbar.
+    try {
+      this._internalRecord(event, details);
+    } catch (ex) {
+      Cu.reportError("Could not record event: " + ex);
+    } finally {
+      this._startEventInfo = null;
+      this._discarded = false;
+    }
+  }
+
+  _internalRecord(event, details) {
+    if (!this._category || !this._startEventInfo) {
+      if (this._discarded && this._category) {
+        this._controller.manager.notifyEngagementChange(
+          this._isPrivate,
+          "discard"
+        );
+      }
+      return;
+    }
+    if (
+      !event &&
+      this._startEventInfo.interactionType != "pasted" &&
+      this._startEventInfo.interactionType != "dropped"
+    ) {
+      // If no event is passed, we must be executing either paste&go or drop&go.
+      throw new Error("Event must be defined, unless input was pasted/dropped");
+    }
+    if (!details) {
+      throw new Error("Invalid event details: " + details);
+    }
+
+    let endTime = (event && event.timeStamp) || Cu.now();
+    let startTime = this._startEventInfo.timeStamp || endTime;
+    // Synthesized events in tests may have a bogus timeStamp, causing a
+    // subtraction between monotonic and non-monotonic timestamps; that's why
+    // abs is necessary here. It should only happen in tests, anyway.
+    let elapsed = Math.abs(Math.round(endTime - startTime));
+
+    let action;
+    if (!event) {
+      action =
+        this._startEventInfo.interactionType == "dropped"
+          ? "drop_go"
+          : "paste_go";
+    } else if (event.type == "blur") {
+      action = "blur";
+    } else {
+      action = event instanceof MouseEvent ? "click" : "enter";
+    }
+    let method = action == "blur" ? "abandonment" : "engagement";
+    let value = this._startEventInfo.interactionType;
+
+    // Rather than listening to the pref, just update status when we record an
+    // event, if the pref changed from the last time.
+    let recordingEnabled = UrlbarPrefs.get("eventTelemetry.enabled");
+    if (this._eventRecordingEnabled != recordingEnabled) {
+      this._eventRecordingEnabled = recordingEnabled;
+      Services.telemetry.setEventRecordingEnabled("urlbar", recordingEnabled);
+    }
+
+    // numWords is not a perfect measurement, since it will return an incorrect
+    // value for languages that do not use spaces or URLs containing spaces in
+    // its query parameters, for example.
+    let extra = {
+      elapsed: elapsed.toString(),
+      numChars: details.searchString.length.toString(),
+      numWords: details.searchString
+        .trim()
+        .split(UrlbarTokenizer.REGEXP_SPACES)
+        .filter(t => t)
+        .length.toString(),
+    };
+    if (method == "engagement") {
+      extra.selIndex = details.selIndex.toString();
+      extra.selType = details.selType;
+      extra.provider = details.provider || "";
+    }
+
+    // We invoke recordEvent regardless, if recording is disabled this won't
+    // report the events remotely, but will count it in the event_counts scalar.
+    Services.telemetry.recordEvent(
+      this._category,
+      method,
+      action,
+      value,
+      extra
+    );
+
+    this._controller.manager.notifyEngagementChange(this._isPrivate, method);
+  }
+
+  /**
+   * Resets the currently tracked user-generated event that was registered via
+   * start(), so it won't be recorded.  If there's no tracked event, this is a
+   * no-op.
+   */
+  discard() {
+    if (this._startEventInfo) {
+      this._startEventInfo = null;
+      this._discarded = true;
+    }
+  }
+
+  /**
+   * Extracts a telemetry type from an element for event telemetry.
+   * @param {Element} element The element to analyze.
+   * @returns {string} a string type for the telemetry event.
+   */
+  typeFromElement(element) {
+    if (!element) {
+      return "none";
+    }
+    let row = element.closest(".urlbarView-row");
+    if (row.result && row.result.providerName != "UrlbarProviderTopSites") {
+      // Element handlers go here.
+      if (
+        row.result.type == UrlbarUtils.RESULT_TYPE.TIP &&
+        element.classList.contains("urlbarView-tip-help")
+      ) {
+        return "tiphelp";
+      }
+    }
+    // Now handle the result.
+    return UrlbarUtils.telemetryTypeFromResult(row.result);
+  }
+}