Reland of Add process uptime metadata event in tracing

base/process/process_info_unittest.cc

+// Copyright 2017 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 "base/process/process_info.h"
+
+#include "base/time/time.h"
+#include "build/build_config.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+#if !defined(OS_IOS)
+TEST(ProcessInfoTest, CreationTime) {
+  Time creation_time = CurrentProcessInfo::CreationTime();
+  ASSERT_FALSE(creation_time.is_null());
+}
+#endif  // !defined(OS_IOS)
+
+}  // namespace base