[CrOS] Make UserSessionManager.RestoreOnCrash.AccountIdValid obsolete

Was introduced in https://codereview.chromium.org/2752873002

Fixed: 1165252
Change-Id: Ie3c432d79c5ba216410ad211bbcf46cc6e1d6c6e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2640454Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Commit-Queue: Roman Sorokin [CET] <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845611}

chrome/browser/chromeos/login/session/user_session_manager.cc

@@ -21,8 +21,6 @@
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
-#include "base/metrics/histogram_functions.h"
-#include "base/metrics/histogram_macros.h"
 #include "base/path_service.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string16.h"
@@ -619,8 +617,6 @@ void UserSessionManager::RestoreAuthenticationSession(Profile* user_profile) {
            .empty();
   if (!account_id_valid)
     LOG(ERROR) << "No account is associated with sign-in manager on restore.";
-  UMA_HISTOGRAM_BOOLEAN("UserSessionManager.RestoreOnCrash.AccountIdValid",
-                        account_id_valid);
 
   DCHECK(user);
   if (network_connection_tracker_ &&

tools/metrics/histograms/histograms_xml/others/histograms.xml

@@ -16871,6 +16871,9 @@ regressions. -->
 
 <histogram name="UserSessionManager.RestoreOnCrash.AccountIdValid"
     enum="BooleanValid" expires_after="2021-02-16">
+  <obsolete>
+    Removed 01/2021.
+  </obsolete>
   <owner>rsorokin@chromium.org</owner>
   <owner>cros-oac@google.com</owner>
   <summary>