Third try at landing gRPC refactoring. Previous issue failed on the waterfall

components/cronet/ios/test/cronet_test_runner.mm

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/at_exit.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/gtest_mac.h"
 
+base::AtExitManager* g_at_exit_ = nullptr;
+
 int main(int argc, char* argv[]) {
+  g_at_exit_ = new base::AtExitManager;
   ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 }