diff --git a/core/marker_manager.js b/core/marker_manager.js
index 82c149052..60cb3b870 100644
--- a/core/marker_manager.js
+++ b/core/marker_manager.js
@@ -10,24 +10,26 @@
  */
 'use strict';
 
-goog.provide('Blockly.MarkerManager');
+goog.module('Blockly.MarkerManager');
+goog.module.declareLegacyNamespace();
 
-goog.require('Blockly.Cursor');
-goog.require('Blockly.Marker');
-
-goog.requireType('Blockly.WorkspaceSvg');
+/* eslint-disable-next-line no-unused-vars */
+const Cursor = goog.requireType('Blockly.Cursor');
+/* eslint-disable-next-line no-unused-vars */
+const Marker = goog.requireType('Blockly.Marker');
+/* eslint-disable-next-line no-unused-vars */
+const WorkspaceSvg = goog.requireType('Blockly.WorkspaceSvg');
 
 
 /**
  * Class to manage the multiple markers and the cursor on a workspace.
- * @param {!Blockly.WorkspaceSvg} workspace The workspace for the marker manager.
+ * @param {!WorkspaceSvg} workspace The workspace for the marker manager.
  * @constructor
- * @package
  */
-Blockly.MarkerManager = function(workspace){
+const MarkerManager = function(workspace) {
   /**
    * The cursor.
-   * @type {?Blockly.Cursor}
+   * @type {?Cursor}
    * @private
    */
   this.cursor_ = null;
@@ -41,14 +43,14 @@ Blockly.MarkerManager = function(workspace){
 
   /**
    * The map of markers for the workspace.
-   * @type {!Object<string, !Blockly.Marker>}
+   * @type {!Object<string, !Marker>}
    * @private
    */
   this.markers_ = Object.create(null);
 
   /**
    * The workspace this marker manager is associated with.
-   * @type {!Blockly.WorkspaceSvg}
+   * @type {!WorkspaceSvg}
    * @private
    */
   this.workspace_ = workspace;
@@ -59,19 +61,19 @@ Blockly.MarkerManager = function(workspace){
  * @type {string}
  * @const
  */
-Blockly.MarkerManager.LOCAL_MARKER = 'local_marker_1';
+MarkerManager.LOCAL_MARKER = 'local_marker_1';
 
 /**
  * Register the marker by adding it to the map of markers.
  * @param {string} id A unique identifier for the marker.
- * @param {!Blockly.Marker} marker The marker to register.
+ * @param {!Marker} marker The marker to register.
  */
-Blockly.MarkerManager.prototype.registerMarker = function(id, marker) {
+MarkerManager.prototype.registerMarker = function(id, marker) {
   if (this.markers_[id]) {
     this.unregisterMarker(id);
   }
-  marker.setDrawer(this.workspace_.getRenderer()
-      .makeMarkerDrawer(this.workspace_, marker));
+  marker.setDrawer(
+      this.workspace_.getRenderer().makeMarkerDrawer(this.workspace_, marker));
   this.setMarkerSvg(marker.getDrawer().createDom());
   this.markers_[id] = marker;
 };
@@ -80,47 +82,48 @@ Blockly.MarkerManager.prototype.registerMarker = function(id, marker) {
  * Unregister the marker by removing it from the map of markers.
  * @param {string} id The ID of the marker to unregister.
  */
-Blockly.MarkerManager.prototype.unregisterMarker = function(id) {
-  var marker = this.markers_[id];
+MarkerManager.prototype.unregisterMarker = function(id) {
+  const marker = this.markers_[id];
   if (marker) {
     marker.dispose();
     delete this.markers_[id];
   } else {
-    throw Error('Marker with ID ' + id + ' does not exist. ' +
+    throw Error(
+        'Marker with ID ' + id + ' does not exist. ' +
         'Can only unregister markers that exist.');
   }
 };
 
 /**
  * Get the cursor for the workspace.
- * @return {?Blockly.Cursor} The cursor for this workspace.
+ * @return {?Cursor} The cursor for this workspace.
  */
-Blockly.MarkerManager.prototype.getCursor = function() {
+MarkerManager.prototype.getCursor = function() {
   return this.cursor_;
 };
 
 /**
  * Get a single marker that corresponds to the given ID.
  * @param {string} id A unique identifier for the marker.
- * @return {?Blockly.Marker} The marker that corresponds to the given ID,
+ * @return {?Marker} The marker that corresponds to the given ID,
  *     or null if none exists.
  */
-Blockly.MarkerManager.prototype.getMarker = function(id) {
+MarkerManager.prototype.getMarker = function(id) {
   return this.markers_[id] || null;
 };
 
 /**
  * Sets the cursor and initializes the drawer for use with keyboard navigation.
- * @param {Blockly.Cursor} cursor The cursor used to move around this workspace.
+ * @param {Cursor} cursor The cursor used to move around this workspace.
  */
-Blockly.MarkerManager.prototype.setCursor = function(cursor) {
+MarkerManager.prototype.setCursor = function(cursor) {
   if (this.cursor_ && this.cursor_.getDrawer()) {
     this.cursor_.getDrawer().dispose();
   }
   this.cursor_ = cursor;
   if (this.cursor_) {
-    var drawer = this.workspace_.getRenderer()
-        .makeMarkerDrawer(this.workspace_, this.cursor_);
+    const drawer = this.workspace_.getRenderer().makeMarkerDrawer(
+        this.workspace_, this.cursor_);
     this.cursor_.setDrawer(drawer);
     this.setCursorSvg(this.cursor_.getDrawer().createDom());
   }
@@ -132,7 +135,7 @@ Blockly.MarkerManager.prototype.setCursor = function(cursor) {
  *     workspace SVG group.
  * @package
  */
-Blockly.MarkerManager.prototype.setCursorSvg = function(cursorSvg) {
+MarkerManager.prototype.setCursorSvg = function(cursorSvg) {
   if (!cursorSvg) {
     this.cursorSvg_ = null;
     return;
@@ -148,7 +151,7 @@ Blockly.MarkerManager.prototype.setCursorSvg = function(cursorSvg) {
  *     workspace SVG group.
  * @package
  */
-Blockly.MarkerManager.prototype.setMarkerSvg = function(markerSvg) {
+MarkerManager.prototype.setMarkerSvg = function(markerSvg) {
   if (!markerSvg) {
     this.markerSvg_ = null;
     return;
@@ -167,7 +170,7 @@ Blockly.MarkerManager.prototype.setMarkerSvg = function(markerSvg) {
  * Redraw the attached cursor SVG if needed.
  * @package
  */
-Blockly.MarkerManager.prototype.updateMarkers = function() {
+MarkerManager.prototype.updateMarkers = function() {
   if (this.workspace_.keyboardAccessibilityMode && this.cursorSvg_) {
     this.workspace_.getCursor().draw();
   }
@@ -179,9 +182,9 @@ Blockly.MarkerManager.prototype.updateMarkers = function() {
  * @suppress {checkTypes}
  * @package
  */
-Blockly.MarkerManager.prototype.dispose = function() {
-  var markerIds = Object.keys(this.markers_);
-  for (var i = 0, markerId; (markerId = markerIds[i]); i++) {
+MarkerManager.prototype.dispose = function() {
+  const markerIds = Object.keys(this.markers_);
+  for (let i = 0, markerId; (markerId = markerIds[i]); i++) {
     this.unregisterMarker(markerId);
   }
   this.markers_ = null;
@@ -190,3 +193,6 @@ Blockly.MarkerManager.prototype.dispose = function() {
     this.cursor_ = null;
   }
 };
+
+/** @package */
+exports = MarkerManager;
diff --git a/tests/deps.js b/tests/deps.js
index 6d78e4217..ae77407c9 100644
--- a/tests/deps.js
+++ b/tests/deps.js
@@ -107,7 +107,7 @@ goog.addDependency('../../core/keyboard_nav/basic_cursor.js', ['Blockly.BasicCur
 goog.addDependency('../../core/keyboard_nav/cursor.js', ['Blockly.Cursor'], ['Blockly.ASTNode', 'Blockly.Marker', 'Blockly.registry', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/keyboard_nav/marker.js', ['Blockly.Marker'], ['Blockly.ASTNode']);
 goog.addDependency('../../core/keyboard_nav/tab_navigate_cursor.js', ['Blockly.TabNavigateCursor'], ['Blockly.ASTNode', 'Blockly.BasicCursor', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
-goog.addDependency('../../core/marker_manager.js', ['Blockly.MarkerManager'], ['Blockly.Cursor', 'Blockly.Marker']);
+goog.addDependency('../../core/marker_manager.js', ['Blockly.MarkerManager'], [], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/menu.js', ['Blockly.Menu'], ['Blockly.browserEvents', 'Blockly.utils.Coordinate', 'Blockly.utils.KeyCodes', 'Blockly.utils.aria', 'Blockly.utils.dom', 'Blockly.utils.style'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/menuitem.js', ['Blockly.MenuItem'], ['Blockly.utils.IdGenerator', 'Blockly.utils.aria', 'Blockly.utils.dom']);
 goog.addDependency('../../core/metrics_manager.js', ['Blockly.FlyoutMetricsManager', 'Blockly.MetricsManager'], ['Blockly.IMetricsManager', 'Blockly.registry', 'Blockly.utils.Size', 'Blockly.utils.toolbox'], {'lang': 'es5'});