[Upstream] Force instantiation of BSKSF during unit tests

ios/chrome/browser/browser_state/browser_state_keyed_service_factories.h

Index: ios/chrome/browser/browser_state/browser_state_keyed_service_factories.h
diff --git a/ios/chrome/browser/browser_state/browser_state_keyed_service_factories.h b/ios/chrome/browser/browser_state/browser_state_keyed_service_factories.h
new file mode 100644
index 0000000000000000000000000000000000000000..d90b1c9e911c77b5274aa3d24842c8f9bdc9f4be
--- /dev/null
+++ b/ios/chrome/browser/browser_state/browser_state_keyed_service_factories.h
@@ -0,0 +1,13 @@
+// Copyright 2015 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.
+
+#ifndef IOS_CHROME_BROWSER_BROWSER_STATE_BROWSER_STATE_KEYED_SERVICE_FACTORIES_H_
+#define IOS_CHROME_BROWSER_BROWSER_STATE_BROWSER_STATE_KEYED_SERVICE_FACTORIES_H_
+
+// Instantiates all KeyedService factories which is especially important for
+// services that register preferences or that should be created at browser
+// state creation time (as opposed to lazily on first access).
+void EnsureBrowserStateKeyedServiceFactoriesBuilt();
+
+#endif  // IOS_CHROME_BROWSER_BROWSER_STATE_BROWSER_STATE_KEYED_SERVICE_FACTORIES_H_