[cros] RLZ tracking can be turned off via a flag file.

rlz/test/rlz_unittest_main.cc

 // Copyright (c) 2012 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.
 //
 // Main entry point for all unit tests.
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "rlz/lib/rlz_lib.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_POSIX)
+#include "base/file_path.h"
+#include "base/files/scoped_temp_dir.h"
+#include "rlz/lib/rlz_value_store.h"
+#endif
+
 int main(int argc, char **argv) {
   base::AtExitManager at_exit;
   CommandLine::Init(argc, argv);
 
   testing::InitGoogleMock(&argc, argv);
   testing::InitGoogleTest(&argc, argv);
 
   int ret = RUN_ALL_TESTS();
   if (ret == 0) {
     // Now re-run all the tests using a supplementary brand code.  This brand
     // code will remain in effect for the lifetime of the branding object.
+#if defined(OS_POSIX)
+    // Set a temporary directory for RLZ here, because SupplementaryBranding
+    // creates and owns RlzValueStore object for its lifetime.
+    base::ScopedTempDir temp_dir;
+    if (temp_dir.CreateUniqueTempDir())
+      rlz_lib::testing::SetRlzStoreDirectory(temp_dir.path());
+#endif
     rlz_lib::SupplementaryBranding branding("TEST");
     ret = RUN_ALL_TESTS();
   }
 
   return ret;
 }