Implement important sites dialog for desktop.

chrome/browser/resources/settings/controls/important_site_checkbox.js

Index: chrome/browser/resources/settings/controls/important_site_checkbox.js
diff --git a/chrome/browser/resources/settings/controls/important_site_checkbox.js b/chrome/browser/resources/settings/controls/important_site_checkbox.js
new file mode 100644
index 0000000000000000000000000000000000000000..3bd2d5d58ecb33d05251bdd76c79329c73d95c8d
--- /dev/null
+++ b/chrome/browser/resources/settings/controls/important_site_checkbox.js
@@ -0,0 +1,35 @@
+// 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.
+
+/**
+ * @fileoverview
+ * `important-site-checkbox` is a checkbox that displays an important site.
+ */
+Polymer({
+  is: 'important-site-checkbox',
+
+  properties: {
+    /** The ImportantSite associated with this checkbox. */
+    site: {
+      type: ImportantSite,
+    },
+
+    /** Whether this checkbox should be disabled. */
+    disabled: {
+      type: Boolean,
+      value: false
+    },
+  },
+
+  /**
+   * Returns the icon to use for a given site.
+   * @param {string} site The url of the site to fetch the icon for.
+   * @return {string} The background-image style with the favicon.
+   * @private
+   */
+  siteIcon_: function(url) {
+    return 'background-image: ' + cr.icon.getFavicon(url);
+  },
+
+});