Split mojo/public/cpp/system/tests/core_unittest.cc, part 1.

mojo/public/cpp/system/tests/time_unittest.cc

+// 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.
+
+// This file tests the C++ wrappers in mojo/public/cpp/system/time.h.
+
+#include "mojo/public/cpp/system/time.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace mojo {
+namespace {
+
+TEST(TimeTest, GetTimeTicksNow) {
+  const MojoTimeTicks start = GetTimeTicksNow();
+  EXPECT_NE(static_cast<MojoTimeTicks>(0), start);
+}
+
+}  // namespace
+}  // namespace mojo