UMA to track the reason for re-auth (draft).

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 61e6f54ea02eb402add99ecef71f6c0091de2e7d..7f7635d7c96ed31de2f72465834824375670b05b 100644
--- a/ui/login/account_picker/screen_account_picker.js
+++ b/ui/login/account_picker/screen_account_picker.js
@@ -167,8 +167,14 @@ login.createScreen('AccountPickerScreen', 'account-picker', function() {
       // Show web authentication if this is not a supervised user.
       if (loginAttempts > MAX_LOGIN_ATTEMPTS_IN_POD &&
           !activatedPod.user.supervisedUser) {
+        chrome.send('maxIncorrectPasswordAttempts',
+            [activatedPod.user.emailAddress]);
         activatedPod.showSigninUI();
       } else {
+        if (loginAttempts == 1) {
+          chrome.send('firstIncorrectPasswordAttempt',
+              [activatedPod.user.emailAddress]);
+        }
         // We want bubble's arrow to point to the first letter of input.
         /** @const */ var BUBBLE_OFFSET = 7;
         /** @const */ var BUBBLE_PADDING = 4;