Use dom-if to hide settings pages and show explicitly.

chrome/browser/resources/settings/settings_page/settings_page_visibility.js

+// Copyright 2015 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.
+
+/**
+ * @fileoverview
+ * Behavior common to all Settings pages

[michaelpg, 2015/12/02 19:22:52]

nit: period. and more accurate comment

[stevenjb, 2015/12/02 21:57:10]

Done.

+ *
+ * Example:
+ *   behaviors: [SettingsPageVisibility],
+ *
+ * @group Chrome UI Behavior

[michaelpg, 2015/12/02 19:22:52]

do we ever plan to use @group for anything?

[stevenjb, 2015/12/02 21:57:10]

Dunno, but we have it everywhere.

+ */
+
+/**
+ * Set this to override page visibility, e.g. in tests.
+ * @type !Object|undefined
+ */
+var SettingPageDefaultVisibility;
+
+/** @polymerBehavior */
+var SettingsPageVisibility = {
+  properties: {
+    /** Dictionary of pages to hide. Includes 'basic' and 'advanced'. */

[michaelpg, 2015/12/02 19:22:52]

Can you provide a more specific /** @type */?

Isn't this more like "dictionary of pages to show"?

Lastly... this doesn't include 'basic' or 'advanced'.

[stevenjb, 2015/12/02 21:57:10]

Opps. It did originally but then I decided that was confusing. Fixed.
As for type, looks like I can use Object.<string, boolean> - I hadn't run into
that before.

+    pageVisible: {
+      type: Object,
+      value: SettingPageDefaultVisibility,
+      notify: true,
+    },
+  },
+
+  /**
+   * Sets the visibility for each page in |pages| to true, causing it to load.
+   * @param {!Array<string>} pages
+   */
+  setVisiblePages: function(pages) {
+    var visible = this.pageVisible || {};

[michaelpg, 2015/12/02 19:22:52]

since setVisiblePages([]) is a no-op (it doesn't hide pages), maybe rename this,
e.g. setPagesVisible?

"set visible pages" --> set the visible pages to these ones
"set pages visible"--> make these pages visible

[stevenjb, 2015/12/02 21:57:10]

That kinda sorta almost makes sense to me :) Done.

+    for (var p of pages) {
+      visible[p] = true;
+    }
+    this.set('pageVisible', visible);

[michaelpg, 2015/12/02 19:22:52]

this.pageVisible = visible

[stevenjb, 2015/12/02 21:57:10]

Done.

+  },
+
+  /**
+   * Sets the visibility for all settings-section entries unless
+   * pageVisible has already been explicitly defined.
+   */
+  showDefaultSections: function() {
+    if (this.pageVisible != undefined)
+      return;
+    var pages = [];
+    var sections = this.shadowRoot.querySelectorAll('settings-section');
+    var len = sections.length;
+    for (var i = 0; i < len; ++i) {
+      pages.push(sections[i].section);
+    }
+    this.setVisiblePages(pages);
+  },
+};