Remove signin_manager_factory.h include from signin_global_error_unittest.cc

This include is not used.

Bug: 927240
Change-Id: Ie6035f1ed59db494cf875118e9dda114d9dbe65e
Reviewed-on: https://chromium-review.googlesource.com/c/1448217Reviewed-by: Mihai Sardarescu <msarda@chromium.org>
Commit-Queue: Henrique Ferreiro <hferreiro@igalia.com>
Cr-Commit-Position: refs/heads/master@{#627963}

chrome/browser/signin/signin_global_error_unittest.cc

@@ -20,7 +20,6 @@
 #include "chrome/browser/signin/identity_test_environment_profile_adaptor.h"
 #include "chrome/browser/signin/signin_error_controller_factory.h"
 #include "chrome/browser/signin/signin_global_error_factory.h"
-#include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/ui/global_error/global_error_service.h"
 #include "chrome/browser/ui/global_error/global_error_service_factory.h"
 #include "chrome/common/pref_names.h"