Added uma for pin unlock set up.

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

Index: chrome/browser/resources/settings/people_page/setup_pin_dialog.js
diff --git a/chrome/browser/resources/settings/people_page/setup_pin_dialog.js b/chrome/browser/resources/settings/people_page/setup_pin_dialog.js
index f299a0eaea31aeff60d99f087c958cead71f0664..0fc7ee0758ebdc2f053e2db570ab8fbbc62af827 100644
--- a/chrome/browser/resources/settings/people_page/setup_pin_dialog.js
+++ b/chrome/browser/resources/settings/people_page/setup_pin_dialog.js
@@ -204,6 +204,9 @@ Polymer({
         this.isConfirmStep_ = true;
         this.onPinChange_();
         this.$.pinKeyboard.focus();
+        chrome.send('metricsHandler:recordInHistogram',
+            [PinUnlockUmaHistogramName, PinUnlockSetupType.ENTER_PIN,
+             PinUnlockSetupType.MAX_BUCKET]);
       }
     } else {
       // onPinSubmit_ gets called if the user hits enter on the PIN keyboard.
@@ -226,6 +229,9 @@ Polymer({
         [chrome.quickUnlockPrivate.QuickUnlockMode.PIN],
         [this.pinKeyboardValue_],
         onSetModesCompleted.bind(this));
+        chrome.send('metricsHandler:recordInHistogram',

[jdufault, 2016/09/13 18:36:05]

fix indentation

[sammiequon, 2016/09/13 19:21:40]

Done.

+            [PinUnlockUmaHistogramName, PinUnlockSetupType.CONFIRM_PIN,
+             PinUnlockSetupType.MAX_BUCKET]);
     }
   },