UMA for pin unlock success/failure.

chrome/browser/chromeos/login/lock/screen_locker.h

Index: chrome/browser/chromeos/login/lock/screen_locker.h
diff --git a/chrome/browser/chromeos/login/lock/screen_locker.h b/chrome/browser/chromeos/login/lock/screen_locker.h
index 856162047e922dc4e36fb28e303bbc31459e5e23..57aca327429f27e6a3610091fd15a483b11268f2 100644
--- a/chrome/browser/chromeos/login/lock/screen_locker.h
+++ b/chrome/browser/chromeos/login/lock/screen_locker.h
@@ -49,6 +49,18 @@ class WebUIScreenLockerTester;
 // instance of itself which will be deleted when the system is unlocked.
 class ScreenLocker : public AuthStatusConsumer {
  public:
+  enum UnlockSuccess {
+    AUTH_SUCCESS_PASSWORD = 0,
+    AUTH_SUCCESS_PIN,
+    AUTH_SUCCESS_COUNT
+  };
+
+  enum UnlockFailure {
+    AUTH_FAILURE_PASSWORD = 0,
+    AUTH_FAILURE_PIN,
+    AUTH_FAILURE_COUNT
+  };
+
   explicit ScreenLocker(const user_manager::UserList& users);
 
   // Returns the default instance if it has been created.