md-settings: Added settings for fingerprint unlock.

chrome/browser/resources/settings/people_page/fingerprint_list.js

+// Copyright 2016 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.
+
+(function() {
+'use strict';
+
+/**
+ * The max number of fingerprints this list can hold.
+ * @const {number}
+ */
+var MAX_NUMBER_FINGERPRINTS_ALLOWED = 5;
+
+Polymer({
+  is: 'settings-fingerprint-list',
+
+  behaviors: [
+    I18nBehavior,
+  ],
+
+  properties: {
+    /**
+     * The list of fingerprint objects.
+     * @private {!Array<string>}
+     */
+    fingerprints_: {
+      type: Array,
+      value: function() {
+        return [];
+      }
+    }
+  },
+
+  /**
+   * Adds a fingerprint with a default name.
+   * @private
+   */
+  onAddFingerprint_: function() {
+    // Determines what the newly added fingerprint's name should be.
+    // TODO(sammiequon): Add fingerprint using private API once it is ready.
+
+    var fingerprintName;
+    for (var i = 1; i <= MAX_NUMBER_FINGERPRINTS_ALLOWED; ++i) {
+      fingerprintName = this.i18n('lockScreenFingerprintNewName', i);
+      if (this.fingerprints_.includes(fingerprintName))
+        continue;
+      break;
+    }
+    this.push('fingerprints_', fingerprintName);

[Dan Beam, 2017/01/26 00:27:27]

this.push('fingerprints_',
    this.i18n('lockScreenFingerprintNewName', this.fingerprints_.length + 1));

[sammiequon, 2017/01/26 00:48:23]

This is a bit different behavior. For example if we have two names 'Finger 1'
and 'Finger 2' and we rename 'Finger 2' to 'Finger', and then add a third
fingerprint, the previous would give a new name of 'Finger 2' while this way
would give a new name of 'Finger 3'.

[Dan Beam, 2017/01/26 04:12:04]

how can you rename fingerprints?

[sammiequon, 2017/01/26 15:56:45]

The fingerprint names on displayed on paper-inputs.

+  },
+
+  /**
+   * Deletes a fingerprint from |fingerprints_|.
+   * @private
+   */
+  onFingerprintDelete_: function(e) {
+    // TODO(sammiequon): Remove fingerprint using private API once it is ready.
+    this.splice('fingerprints_', e.model.index, 1);
+  },
+
+  /**
+   * Returns the text to be displayed for the add fingerprint button.
+   * @param {number} numFingerprints
+   * @return {string}
+   * @private
+   */
+  getFingerprintButtonText_: function(numFingerprints) {
+    if (this.canAddNewFingerprint_(numFingerprints))
+      return this.i18n('lockScreenAddFingerprint');
+
+    return this.i18n('lockScreenCannotAddFingerprint',
+                     MAX_NUMBER_FINGERPRINTS_ALLOWED);
+  },
+
+  /**
+   * Checks whether another fingerprint can be added.
+   * @param {number} numFingerprints
+   * @return {boolean}
+   * @private
+   */
+  canAddNewFingerprint_: function(numFingerprints) {

[Dan Beam, 2017/01/26 00:27:27]

canAddNewFingerprint_: function() {
  return this.fingerprints_.length < MAX_NUMBER_FINGERPRINTS_ALLOWED;
},

[sammiequon, 2017/01/26 00:48:23]

I tried that but this function does not fire when I add/delete a fingerprint,
with or without notifyResize.
https://www.polymer-project.org/1.0/docs/devguide/data-binding#annotated-comp...
- 'it is only computed once if it has no dependencies', but we need it to
recompute everytime we add/delete.

[Dan Beam, 2017/01/26 04:12:04]

fingerprints_.*?

[sammiequon, 2017/01/26 15:56:45]

Done.

[Dan Beam, 2017/01/27 01:14:15]

no, i mean, in the binding, [[canAddNewFingerprint_(fingerprints_.*)]]

[sammiequon, 2017/01/27 23:04:58]

Done.

+    return numFingerprints < MAX_NUMBER_FINGERPRINTS_ALLOWED;
+  }
+});
+})();