Rolling forward https://codereview.chromium.org/1155683008/ which was

third_party/polymer/v0_8/components-chromium/more-routing/driver/path-extracted.js

-
-(function(scope) {
-var MoreRouting = scope.MoreRouting = scope.MoreRouting || {};
-MoreRouting.PathDriver = PathDriver;
-
-/**
- * TODO(nevir): Docs.
- */
-function PathDriver() {
-  MoreRouting.Driver.apply(this, arguments);
-  this._bindEvents();
-  this._read();
-}
-PathDriver.prototype = Object.create(MoreRouting.Driver.prototype);
-
-PathDriver.prototype.navigateToUrl = function navigateToUrl(url) {
-  window.history.pushState({}, '', url);
-  this._read();
-};
-
-PathDriver.prototype._bindEvents = function _bindEvents() {
-  window.addEventListener('popstate', this._read.bind(this));
-};
-
-PathDriver.prototype._read = function _read() {
-  this.setCurrentPath(window.location.pathname);
-};
-
-})(window);