Added uma for pin unlock set up.

chrome/browser/resources/settings/people_page/lock_screen_constants.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.
+
+/**
+ * @fileoverview Constants used for logging the pin unlock setup uma.
+ */
+
+/**
+ * Name of the pin unlock setup uma histogram.
+ * @type {string}
+ */
+var PinUnlockUmaHistogramName = 'Settings.PinUnlockSetup';
+
+/**
+ * Stages the user can enter while setting up pin unlock.
+ * @enum {number}
+ */
+var LockScreenProgress = {
+  START_SCREEN_LOCK: 0,
+  ENTER_PASSWORD_CORRECTLY: 1,
+  CHOOSE_PIN_OR_PASSWORD: 2,
+  ENTER_PIN: 3,
+  CONFIRM_PIN: 4,
+  MAX_BUCKET: 5
+};
+
+/**
+ * Helper function to send the progress of the pin setup to be recorded in the
+ * histogram.
+ * @param {number} currentProgress

[jdufault, 2016/09/13 19:36:35]

@param {LockScreenProgress} currentProgress

[sammiequon, 2016/09/13 21:34:57]

Done.

+ */
+var recordLockScreenProgress = function(currentProgress) {
+  if (currentProgress >= LockScreenProgress.MAX_BUCKET)

[jdufault, 2016/09/13 19:36:35]

Log an error?

[sammiequon, 2016/09/13 21:34:58]

Done.

+    return;
+  chrome.send('metricsHandler:recordInHistogram',
+      [PinUnlockUmaHistogramName, currentProgress,
+       LockScreenProgress.MAX_BUCKET]);
+};