removed unnecessary defderred PrepareTpmDeviceAndFinalizeProfile

According to the current program flow, this to-be-removed branch seems a
useless special handling.

This CL might affect how UserSessionManager utilitzes tpm manager client
in the near future.

BUG=b:172748724
TEST=unittests.

Change-Id: I93f05a45409878db1138c8d49d835f1d7f0c427e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2525471Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Commit-Queue: Leo Lai <cylai@google.com>
Cr-Commit-Position: refs/heads/master@{#826319}

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

@@ -1522,16 +1522,6 @@ void UserSessionManager::UserProfileInitialized(Profile* profile,
     return;
   }
 
-  if (user_context_.GetAuthFlow() == UserContext::AUTH_FLOW_ACTIVE_DIRECTORY) {
-    // Call FinalizePrepareProfile directly and skip RestoreAuthSessionImpl
-    // because there is no need to merge session for Active Directory users.
-    base::ThreadTaskRunnerHandle::Get()->PostTask(
-        FROM_HERE,
-        base::BindOnce(&UserSessionManager::PrepareTpmDeviceAndFinalizeProfile,
-                       AsWeakPtr(), profile));
-    return;
-  }
-
   PrepareTpmDeviceAndFinalizeProfile(profile);
 }