Add a new function for getting a deterministic machine ID

chrome/browser/prefs/tracked/device_id_unittest.cc

+// 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.
+
+#include "build/build_config.h"
+#include "chrome/browser/prefs/tracked/device_id.h"

[grt (UTC plus 2), 2015/01/27 21:08:45]

move above line 5 with a blank line after it

[gab, 2015/01/27 21:20:30]

Interesting, I've heard the opposite (and am the one who suggested moving it in
here), but from
https://groups.google.com/a/chromium.org/forum/#!searchin/chromium-dev/test$2...
it seems you're right.

I remember Alexei had asked me to move one way or another with a link to a
chromium-dev thread at some point, but I can't find the recommendation, Alexei
do you have an opinion on this?

[Alexei Svitkine (slow), 2015/01/27 22:45:44]

I believe the recommended style in Chromium is now to have it at the top. (Both
are OK according to style guide, but Chromium has been moving to that one.)

+#include "testing/gtest/include/gtest/gtest.h"
+
+TEST(GetDeterministicMachineSpecificIdTest, IsDeterministic) {
+  std::string first_machine_id;
+  std::string second_machine_id;
+
+  const MachineIdStatus kExpectedStatus =
+#if defined(OS_WIN)
+      MachineIdStatus::SUCCESS;
+#else
+      MachineIdStatus::NOT_IMPLEMENTED;
+#endif
+
+  ASSERT_EQ(kExpectedStatus,
+            GetDeterministicMachineSpecificId(&first_machine_id));
+  ASSERT_EQ(kExpectedStatus,
+            GetDeterministicMachineSpecificId(&second_machine_id));
+
+  EXPECT_EQ(kExpectedStatus == MachineIdStatus::SUCCESS,
+            !first_machine_id.empty());
+  EXPECT_EQ(first_machine_id, second_machine_id);
+}