Cleanup bits of base::ProcessMetrics.

base/process/process_metrics_mac.cc

 // Copyright (c) 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_metrics.h"
 
 #include <mach/mach.h>
 #include <mach/mach_vm.h>
 #include <mach/shared_region.h>
 #include <sys/sysctl.h>
@@ skipping 294 matching lines @@
 
   if (last_absolute_idle_wakeups_ == 0) {
     // First call, just set the last values.
     last_idle_wakeups_time_ = time;
     last_absolute_idle_wakeups_ = absolute_idle_wakeups;
     return 0;
   }
 
   int64 wakeups_delta = absolute_idle_wakeups - last_absolute_idle_wakeups_;
   int64 time_delta = (time - last_idle_wakeups_time_).InMicroseconds();
-  DCHECK_NE(0U, time_delta);
-  if (time_delta == 0)
+  if (time_delta == 0) {
+    NOTREACHED();
     return 0;
+  }
 
   last_idle_wakeups_time_ = time;
   last_absolute_idle_wakeups_ = absolute_idle_wakeups;
 
   // Round to average wakeups per second.
   const int kMicrosecondsPerSecond = 1000 * 1000;
   return (wakeups_delta * kMicrosecondsPerSecond + time_delta/2) / time_delta;
 }
 
 bool ProcessMetrics::GetIOCounters(IoCounters* io_counters) const {
@@ skipping 28 matching lines @@
                                      &count);
   if (kr != KERN_SUCCESS) {
     MACH_DLOG(WARNING, kr) << "host_statistics";
     return 0;
   }
 
   return (data.active_count * PAGE_SIZE) / 1024;
 }
 
 }  // namespace base