Revert of Add process uptime metadata event in tracing

base/process/process_info_linux.cc

 // Copyright 2013 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 <stdint.h>
 
 #include "base/logging.h"
 #include "base/process/internal_linux.h"
 #include "base/process/process_handle.h"
 #include "base/time/time.h"
 
 namespace base {
 
 // static
 const Time CurrentProcessInfo::CreationTime() {
   int64_t start_ticks =
       internal::ReadProcSelfStatsAndGetFieldAsInt64(internal::VM_STARTTIME);
-  if (!start_ticks)
-    return Time();
+  DCHECK(start_ticks);
   TimeDelta start_offset = internal::ClockTicksToTimeDelta(start_ticks);
   Time boot_time = internal::GetBootTime();
-  if (boot_time.is_null())
-    return Time();
+  DCHECK(!boot_time.is_null());
   return Time(boot_time + start_offset);
 }
 
 }  // namespace base