[Mac] User manager should show up as a standalone window.

chrome/browser/browser_process_impl.cc

Index: chrome/browser/browser_process_impl.cc
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index 74597c3fef4339979c02b4ccedb8650d4e12120a..a79c5c254658170bd1601cd80c80742f420aba5a 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -60,6 +60,7 @@
 #include "chrome/browser/printing/print_job_manager.h"
 #include "chrome/browser/printing/print_preview_dialog_controller.h"
 #include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/profiles/profiles_state.h"
 #include "chrome/browser/renderer_host/chrome_resource_dispatcher_host_delegate.h"
 #include "chrome/browser/safe_browsing/safe_browsing_service.h"
 #include "chrome/browser/shell_integration.h"
@@ -67,6 +68,7 @@
 #include "chrome/browser/storage_monitor/storage_monitor.h"
 #include "chrome/browser/thumbnails/render_widget_snapshot_taker.h"
 #include "chrome/browser/ui/bookmarks/bookmark_prompt_controller.h"
+#include "chrome/browser/ui/browser_dialogs.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/web_resource/promo_resource_service.h"
 #include "chrome/common/chrome_constants.h"
@@ -248,6 +250,10 @@ void BrowserProcessImpl::StartTearDown() {
   {
     TRACE_EVENT0("shutdown",
                  "BrowserProcessImpl::StartTearDown:ProfileManager");
+    // The desktop User Manager needs to be closed before the guest profile
+    // can be destroyed.
+    if (profiles::IsNewProfileManagementEnabled())
+      chrome::HideUserManager();
     profile_manager_.reset();
   }