ash: Add a DWC to investigate unexpected LoggedInStateChanged

b/333262357 shows a case that `LoggedInStateChanged` could be
called unexpectedly to start the login animation timeout timer.
Add a DWC to investigate how it happens. This should suppress
the DWC in OnLoginAnimationFinishedTimerFired.

Bug: 333262357
Change-Id: I8d3484a5fce28a423407e7382dd5d7399369c77d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5436995
Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1284617}

ash/metrics/login_unlock_throughput_recorder.cc

@@ -244,6 +244,7 @@ void LoginUnlockThroughputRecorder::OnAuthSuccess() {
 }
 
 void LoginUnlockThroughputRecorder::OnAshRestart() {
+  is_ash_restart_ = true;
   login_animation_finished_timer_.Stop();
   if (!post_login_deferred_task_runner_->Started()) {
     post_login_deferred_task_runner_->Start();
@@ -270,6 +271,20 @@ void LoginUnlockThroughputRecorder::LoggedInStateChanged() {
     return;
   }
 
+  // On ash restart, `SessionManager::CreateSessionForRestart` should happen
+  // and trigger `LoggedInStateChanged` here to set `user_logged_in_` flag
+  // before `OnAshRestart` is called. So `is_ash_restart_` should never be true
+  // here. Otherwise, we have unexpected sequence of events and login metrics
+  // would not be correctly reported.
+  //
+  // It seems somehow happening in b/333262357. Adding a DumpWithoutCrashing
+  // to capture the offending stack.
+  // TODO(b/333262357): Remove `DumpWithoutCrashing`.
+  if (is_ash_restart_) {
+    base::debug::DumpWithoutCrashing();
+    return;
+  }
+
   user_logged_in_ = true;
 
   // Report UserLoggedIn histogram if we had OnAuthSuccess() event previously.

ash/metrics/login_unlock_throughput_recorder.h

@@ -224,6 +224,9 @@ class ASH_EXPORT LoginUnlockThroughputRecorder : public SessionObserver,
   // final.
   bool first_restored_window_created_ = false;
 
+  // Whether ash is restarted (due to crash, or applying flags etc).
+  bool is_ash_restart_ = false;
+
   std::optional<base::TimeTicks> arc_opt_in_time_;
 
   base::WeakPtr<ui::TotalAnimationThroughputReporter>