Handle null timer values when profiling sections

base/tracked_objects.cc

 // Copyright (c) 2011 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/tracked_objects.h"
 
 #include <math.h>
 
 #include "base/format_macros.h"
 #include "base/message_loop.h"
@@ skipping 513 matching lines @@
   // that our data structures (which counted the outstanding births) remain
   // consistent.
   if (!birth)
     return;
 
   ThreadData* current_thread_data = Get();
   if (!current_thread_data)
     return;
 
   DurationInt queue_duration = 0;
-  DurationInt run_duration = (end_of_run - start_of_run).InMilliseconds();
+  DurationInt run_duration = 0;
+  if (!start_of_run.is_null() && !end_of_run.is_null())
+    run_duration = (end_of_run - start_of_run).InMilliseconds();
   current_thread_data->TallyADeath(*birth, queue_duration, run_duration);
 }
 
 
 
 // static
 ThreadData* ThreadData::first() {
   base::AutoLock lock(*list_lock_.Pointer());
   return all_thread_data_list_head_;
 }
@@ skipping 723 matching lines @@
                         (combined_selectors_ & BIRTH_THREAD) ? "*" :
                           sample.birth().birth_thread()->thread_name().c_str(),
                         (combined_selectors_ & DEATH_THREAD) ? "*" :
                           sample.DeathThreadName().c_str());
   sample.birth().location().Write(!(combined_selectors_ & BIRTH_FILE),
                                   !(combined_selectors_ & BIRTH_FUNCTION),
                                   output);
 }
 
 }  // namespace tracked_objects