cros: Fixed 3 bugs for pin unlock.

ui/login/account_picker/screen_account_picker.js

Index: ui/login/account_picker/screen_account_picker.js
diff --git a/ui/login/account_picker/screen_account_picker.js b/ui/login/account_picker/screen_account_picker.js
index 69c5eafe3dbb55e5b6523da09c79a181a2be8fd0..c7264894f8d2d4e9dae63abcb871cbcbdfc0bb2e 100644
--- a/ui/login/account_picker/screen_account_picker.js
+++ b/ui/login/account_picker/screen_account_picker.js
@@ -249,6 +249,14 @@ login.createScreen('AccountPickerScreen', 'account-picker', function() {
       if (Oobe.getInstance().displayType == DISPLAY_TYPE.DESKTOP_USER_MANAGER)
         $('login-header-bar').classList.toggle('shadow', users.length > 8);
 
+      // Disable pin for users which should not be able to access pin. Such
+      // users include those who have not set up pin as those who have not
+      // entered their password recently.
+      for (var i in users) {

[jdufault, 2016/10/19 18:12:29]

Don't we usually do a for (var i = 0; i < users.length; ++i) {} loop? iirc, I
think there are subtle gotchas with this form.

[sammiequon, 2016/10/19 21:08:10]

Done.

+        if (!users[i].showPin)
+          this.disablePinKeyboardForUser(users[i].username);

[jdufault, 2016/10/19 18:12:29]

Why not put this inside of loadPinKeyboardIfNeeded_? Maybe rename that method to
initializePinKeyboardStateForUsers_?

[sammiequon, 2016/10/19 21:08:10]

Done.

+      }
+
       this.loadPinKeyboardIfNeeded_(users);
     },