MD Bookmarks: Remove '/?id=1' from URL when displaying Bookmarks Bar

chrome/browser/resources/md_bookmarks/router.js

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 Polymer({
   /**
    * This element is a one way bound interface that routes the page URL to
    * the searchTerm and selectedId. Clients must initialize themselves by
    * reading the router's fields after attach.
    */
   is: 'bookmarks-router',
 
   behaviors: [
     bookmarks.StoreClient,
   ],
 
   properties: {
     /**
      * Parameter q is routed to the searchTerm.
      * Parameter id is routed to the selectedId.
      * @private
      */
     queryParams_: Object,
 
     /** @private */
-    searchTerm_: String,
+    searchTerm_: {
+      type: String,
+      value: '',
+    },
 
     /** @private {?string} */
     selectedId_: String,
   },
 
   observers: [
-    'onQueryChanged_(queryParams_.q)',
-    'onFolderChanged_(queryParams_.id)',
+    'onQueryParamsChanged_(queryParams_)',
     'onStateChanged_(searchTerm_, selectedId_)',
   ],
 
   attached: function() {
     this.watch('selectedId_', function(state) {
       return state.selectedFolder;
     });
     this.watch('searchTerm_', function(state) {
       return state.search.term;
     });
     this.updateFromStore();
   },
 
   /** @private */
-  onQueryChanged_: function() {
+  onQueryParamsChanged_: function() {
     var searchTerm = this.queryParams_.q || '';
-    if (searchTerm && searchTerm != this.searchTerm_) {
+    var selectedId = this.queryParams_.id;
+    if (!selectedId && !searchTerm)
+      selectedId = BOOKMARKS_BAR_ID;
+
+    if (searchTerm != this.searchTerm_) {
       this.searchTerm_ = searchTerm;
       this.dispatch(bookmarks.actions.setSearchTerm(searchTerm));
     }
-  },
 
-  /** @private */
-  onFolderChanged_: function() {
-    var selectedId = this.queryParams_.id;
     if (selectedId && selectedId != this.selectedId_) {
       this.selectedId_ = selectedId;
       // Need to dispatch a deferred action so that during page load
       // `this.getState()` will only evaluate after the Store is initialized.
       this.dispatchAsync(function(dispatch) {
         dispatch(
             bookmarks.actions.selectFolder(selectedId, this.getState().nodes));
       }.bind(this));
     }
   },
 
   /** @private */
   onStateChanged_: function() {
     this.debounce('updateQueryParams', this.updateQueryParams_.bind(this));
   },
 
   /** @private */
   updateQueryParams_: function() {
     if (this.searchTerm_)
       this.queryParams_ = {q: this.searchTerm_};
+    else if (this.selectedId_ != BOOKMARKS_BAR_ID)
+      this.queryParams_ = {id: this.selectedId_};
     else
-      this.queryParams_ = {id: this.selectedId_};
+      this.queryParams_ = {};
   },
 });