PM: Move Variable content testing logic into a common unittest module.

Testing the content of variables is done frequently when testing various
providers. This results in plenty of boilerplate code, as well as
numerous friend declarations in the different FooVariable class
definitions.

This CL introduces a PmTestUtils helper class providing common Variable
testing methods that test fixtures can use.

BUG=chromium:366259
TEST=Unit tests.

Change-Id: I7bb1cea080c3b79c203607550259f4c277e84f3b
Reviewed-on: https://chromium-review.googlesource.com/196529
Tested-by: Gilad Arnold <garnold@chromium.org>
Reviewed-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
diff --git a/policy_manager/pmtest_utils.cc b/policy_manager/pmtest_utils.cc
new file mode 100644
index 0000000..569648e
--- /dev/null
+++ b/policy_manager/pmtest_utils.cc
@@ -0,0 +1,13 @@
+// Copyright (c) 2014 The Chromium OS 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/time/time.h>
+
+#include "update_engine/policy_manager/pmtest_utils.h"
+
+namespace chromeos_policy_manager {
+
+const unsigned PmTestUtils::kDefaultTimeoutInSeconds = 1;
+
+}  // namespace chromeos_policy_manager