Add settings screen that lets a user setup a PIN to unlock their device with.

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

Index: chrome/browser/resources/settings/people_page/quick_unlock_setup_pin.js
diff --git a/chrome/browser/resources/settings/people_page/quick_unlock_setup_pin.js b/chrome/browser/resources/settings/people_page/quick_unlock_setup_pin.js
new file mode 100644
index 0000000000000000000000000000000000000000..0d47e63d1e57cac16acda09601d8508f05a71ecc
--- /dev/null
+++ b/chrome/browser/resources/settings/people_page/quick_unlock_setup_pin.js
@@ -0,0 +1,300 @@
+// 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.
+
+/**
+ * @fileoverview
+ * 'settings-quick-unlock-setup-pin' is the settings page for choosing a PIN.
+ *
+ * Example:
+ *
+ * <settings-quick-unlock-setup-pin
+ *   set-modes="[[quickUnlockSetModes]]"
+ *   current-route="{{currentRoute}}">
+ * </settings-quick-unlock-setup-pin>
+ */
+
+(function() {
+'use strict';
+
+/**
+ * Metainformation about a problem message to pass to showProblem. |class| is
+ * the css class to show the problem message with. |messageId| is the i18n
+ * string id to use.
+ * @const
+ */
+var ProblemInfo = {
+  TOO_SHORT: {
+    messageId: 'quickUnlockConfigurePinChoosePinTooShort',
+    class: 'error'
+  },
+  WEAK: {
+    messageId: 'quickUnlockConfigurePinChoosePinWeakPinWarning',
+    class: 'warning'
+  },
+  MISMATCHED: {
+    messageId: 'quickUnlockConfigurePinMismatchedPins',
+    class: 'error'
+  }
+};
+
+/**
+ * A list of the top-10 most commmonly used PINs. This list is taken from
+ * www.datagenetics.com/blog/september32012/.
+ * @const
+ */
+var WEAK_PINS = [
+  '1234', '1111', '0000', '1212', '7777', '1004', '2000', '4444', '2222',
+  '6969'
+];
+
+Polymer({
+  is: 'settings-quick-unlock-setup-pin',
+
+  behaviors: [
+    QuickUnlockPasswordDetectBehavior,
+    I18nBehavior
+  ],
+
+  properties: {
+    /**
+     * The current PIN keyboard value.
+     * @private
+     */
+    pinKeyboardValue_: String,
+
+    /**
+     * Stores the initial PIN value so it can be confirmed.
+     * @private
+     */
+    initialPin_: String,
+
+    /**
+     * The actual problem message to display.
+     * @private
+     */
+    problemMessage_: String,
+
+    /**
+     * The type of problem class to show (warning or error).
+     */
+    problemClass_: String,
+
+    /**
+     * Should the step-specific submit button be displayed?
+     * @private
+     */
+    enableSubmit_: Boolean,
+
+    /**
+     * The current step/subpage we are on.
+     * @private
+     */
+    isConfirmStep_: {
+      type: Boolean,
+      value: false
+    },
+  },
+
+  observers: [
+    'onRouteChanged_(currentRoute)',
+    'onSetModesChanged_(setModes)'
+  ],
+
+  /** @override */
+  attached: function() {
+    this.resetState_();
+    this.askForPasswordIfUnset();
+  },
+
+  /**
+   * @param {!SettingsRoute} currentRoute
+   * @private
+   */
+  onRouteChanged_: function(currentRoute) {
+    if (this.isScreenActive(QuickUnlockScreen.SETUP_PIN)) {
+      this.askForPasswordIfUnset();
+    } else {
+      // If the user hits the back button, they can leave the element
+      // half-completed; therefore, reset state if the element is not active.
+      this.resetState_();
+    }
+  },
+
+  /** @private */
+  onSetModesChanged_: function() {
+    if (this.isScreenActive(QuickUnlockScreen.SETUP_PIN))
+      this.askForPasswordIfUnset();
+  },
+
+  /**
+   * Resets the element to the initial state.
+   * @private
+   */
+  resetState_: function() {
+    this.initialPin_ = '';
+    this.pinKeyboardValue_ = '';
+    this.enableSubmit_ = false;
+    this.isConfirmStep_ = false;
+    this.onPinChange_();
+  },
+
+  /**
+   * Returns true if the given PIN is likely easy to guess.
+   * @private
+   * @param {string} pin
+   * @return {boolean}
+   */
+  isPinWeak_: function(pin) {
+    // Warn if it's a top-10 pin.
+    if (WEAK_PINS.includes(pin))
+      return true;
+
+    // Warn if the PIN is consecutive digits.
+    var delta = 0;
+    for (var i = 1; i < pin.length; ++i) {
+      var prev = Number(pin[i - 1]);
+      var num = Number(pin[i]);
+      if (Number.isNaN(prev) || Number.isNaN(num))
+        return false;
+      delta = Math.max(delta, Math.abs(num - prev));
+    }
+
+    return delta <= 1;
+  },
+
+  /**
+   * Returns true if the given PIN matches PIN requirements, such as minimum
+   * length.
+   * @private
+   * @param {string|undefined} pin
+   * @return {boolean}
+   */
+  isPinLongEnough_: function(pin) {
+    return !!pin && pin.length >= 4;
+  },
+
+  /**
+   * Returns true if the PIN is ready to be changed to a new value.
+   * @private
+   * @return {boolean}
+   */
+  canSubmit_: function() {
+    return this.isPinLongEnough_(this.pinKeyboardValue_) &&
+           this.initialPin_ == this.pinKeyboardValue_;
+  },
+
+  /**
+   * Notify the user about a problem.
+   * @private
+   * @param {!{messageId: string, class: string}} problemInfo
+   */
+  showProblem_: function(problemInfo) {
+    this.problemMessage_ = this.i18n(problemInfo.messageId);
+    this.problemClass_ = problemInfo.class;
+    this.updateStyles();
+  },
+
+  /** @private */
+  hideProblem_: function() {
+    this.problemMessage_ = '';
+    this.problemClass_ = '';
+  },
+
+  /** @private */
+  onPinChange_: function() {
+    if (!this.isConfirmStep_) {
+      var isPinLongEnough = this.isPinLongEnough_(this.pinKeyboardValue_);
+      var isWeak = isPinLongEnough && this.isPinWeak_(this.pinKeyboardValue_);
+
+      if (!isPinLongEnough && this.pinKeyboardValue_)
+        this.showProblem_(ProblemInfo.TOO_SHORT);
+      else if (isWeak)
+        this.showProblem_(ProblemInfo.WEAK);
+      else
+        this.hideProblem_();
+
+      this.enableSubmit_ = isPinLongEnough;
+
+    } else {
+      var canSubmit = this.canSubmit_();
+
+      if (!canSubmit && this.pinKeyboardValue_)
+        this.showProblem_(ProblemInfo.MISMATCHED);
+      else
+        this.hideProblem_();
+
+      this.enableSubmit_ = canSubmit;
+    }
+  },
+
+  /** @private */
+  onPinSubmit_: function() {
+    if (!this.isConfirmStep_) {
+      if (this.isPinLongEnough_(this.pinKeyboardValue_)) {
+        this.initialPin_ = this.pinKeyboardValue_;
+        this.pinKeyboardValue_ = '';
+        this.isConfirmStep_ = true;
+        this.onPinChange_();
+      }
+    } else {
+      // onPinSubmit_ gets called if the user hits enter on the PIN keyboard.
+      // The PIN is not guaranteed to be valid in that case.
+      if (!this.canSubmit_())
+        return;
+
+      function onSetModesCompleted(didSet) {
+        if (!didSet) {
+          console.error('Failed to update pin');
+          return;
+        }
+
+        this.resetState_();
+        this.currentRoute = {
+          page: 'basic',
+          section: 'people',
+          subpage: [QuickUnlockScreen.CHOOSE_METHOD]
+        };
+      }
+
+      this.setModes.call(
+        null,
+        [chrome.quickUnlockPrivate.QuickUnlockMode.PIN],
+        [this.pinKeyboardValue_],
+        onSetModesCompleted.bind(this));
+    }
+  },
+
+  /**
+   * @private
+   * @param {string} problemMessage
+   * @return {boolean}
+   */
+  hasProblem_: function(problemMessage) {
+    return !!problemMessage;
+  },
+
+  /**
+   * @private
+   * @param {boolean} isConfirmStep
+   * @return {string}
+   */
+  getTitleMessage_: function(isConfirmStep) {
+    if (!isConfirmStep)
+      return this.i18n('quickUnlockConfigurePinChoosePinTitle');
+    return this.i18n('quickUnlockConfigurePinConfirmPinTitle');
+  },
+
+  /**
+   * @private
+   * @param {boolean} isConfirmStep
+   * @return {string}
+   */
+  getContinueMessage_: function(isConfirmStep) {
+    if (!isConfirmStep)
+      return this.i18n('quickUnlockConfigurePinContinueButton');
+    return this.i18n('save');
+  },
+});
+
+})();