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..07092c45491e8f9f81812b360393b17dda30319f 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 UnlockSuccessType {

[jdufault, 2016/08/04 19:42:04]

Just UnlockSuccess

[jdufault, 2016/08/04 19:42:04]

use enum class

[sammiequon, 2016/08/05 01:46:00]

Im not sure if UMA_HISTOGRAM_ENUM is compatible with enum class. At least the
handful of histograms i looked at all use enum.

[sammiequon, 2016/08/05 01:46:00]

Done.

[jdufault, 2016/08/08 18:54:25]

Why not? Does something like this work?

  enum class Foo : int { /* ... */ }

[sammiequon, 2016/08/09 00:31:25]

That does not work either. It doesn't build with enum class i tried to cast and
that stuff.

[jdufault, 2016/08/12 21:57:33]

Ok; do you happen to recall the error message?

[sammiequon, 2016/08/16 17:29:09]

Invalid operands to binary expression ('chromeos::ScreenLocker::UnlockSuccess'
and 'int') and
cannot initialize a parameter of type 'Sample' (aka 'int') with an rvalue of
type 'chromeos::ScreenLocker::UnlockSuccess'

+    AUTH_SUCCESS_PASSWORD = 0,
+    AUTH_SUCCESS_PIN,
+    AUTH_SUCCESS_TYPE_NUM

[jdufault, 2016/08/04 19:42:04]

AUTH_SUCCESS_COUNT or AUTH_SUCCESS_MAX_VALUE

[sammiequon, 2016/08/05 01:45:59]

Done.

+  };
+
+  enum UnlockFailureType {

[jdufault, 2016/08/04 19:42:04]

enum class

[jdufault, 2016/08/04 19:42:04]

Just UnlockFailure

[sammiequon, 2016/08/05 01:45:59]

Done.

+    AUTH_FAILURE_PASSWORD = 0,
+    AUTH_FAILURE_PIN,
+    AUTH_FAILURE_TYPE_NUM

[jdufault, 2016/08/04 19:42:04]

AUTH_FAILURE_COUNT or AUTH_FAILURE_MAX_VALUE

[sammiequon, 2016/08/05 01:45:59]

Done.

+  };
+
   explicit ScreenLocker(const user_manager::UserList& users);
 
   // Returns the default instance if it has been created.