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() {

[Dan Beam, 2017/01/10 23:23:45]

onAddFingerprint_: function() {
  var numPrints = this.fingerprints_.length;
  if (!this.canAddNewFingerPrint_(numPrints))
    return;
  var printName = this.i18n('lockScreenFingerprintNewName', numPrints);
  this.push('fingerprints_', printName);

[sammiequon, 2017/01/11 00:29:09]

This would give something slightly different than the old code. For example
create a new fingerprint 'Finger 0', rename it to 'Finger 1' then create a new
fingerprint. The new fingerprint would be 'Finger 1' where the old one would be
'Finger 0'.

+    // 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);
+    this.$.fingerprintsList.notifyResize();

[Dan Beam, 2017/01/10 23:23:46]

why do you need notifyResize()?

[sammiequon, 2017/01/11 00:29:09]

Done.

[sammiequon, 2017/01/17 19:59:09]

Actually, without this, on options the list does not update. On settings it's
fine.

+  },
+
+  /**
+   * 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);
+    this.$.fingerprintsList.notifyResize();

[Dan Beam, 2017/01/10 23:23:45]

why do you need notifyResize()?

[sammiequon, 2017/01/11 00:29:09]

Done.

+  },
+
+  /**
+   * 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) {
+    return numFingerprints < MAX_NUMBER_FINGERPRINTS_ALLOWED;

[Dan Beam, 2017/01/10 23:23:45]

you only ever pass this.fingerprints_.length for numFingerprints, afaict.  could
you just do this instead?

this.fingerprints_.length < MAX_NUMBER_FINGERPRINTS_ALLOWED;

[sammiequon, 2017/01/11 00:29:09]

That is correct. If I do it that way,
canAddNewFingerprint_/getFingerprintButtonText_ don't get called when a print is
added/deleted.

+  }
+});
+})();