Log histograms on shutdown when verbose logging is on

base/metrics/statistics_recorder.cc

 // Copyright (c) 2012 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/metrics/statistics_recorder.h"
 
 #include <memory>
 
 #include "base/at_exit.h"
 #include "base/debug/leak_annotations.h"
@@ skipping 320 matching lines @@
 StatisticsRecorder::HistogramIterator StatisticsRecorder::end() {
   HistogramMap::iterator iter_end;
   {
     base::AutoLock auto_lock(*lock_);
     iter_end = histograms_->end();
   }
   return HistogramIterator(iter_end, true);
 }
 
 // static
+void StatisticsRecorder::InitLogOnShutdown() {
+  if (lock_ == nullptr)
+    return;
+  base::AutoLock auto_lock(*lock_);
+  g_statistics_recorder_.Get().InitLogOnShutdownWithoutLock();
+}
+
+// static
 void StatisticsRecorder::GetSnapshot(const std::string& query,
                                      Histograms* snapshot) {
   if (lock_ == NULL)
     return;
   base::AutoLock auto_lock(*lock_);
   if (histograms_ == NULL)
     return;
 
   for (const auto& entry : *histograms_) {
     if (entry.second->histogram_name().find(query) != std::string::npos)
@@ skipping 124 matching lines @@
   base::AutoLock auto_lock(*lock_);
 
   existing_histograms_.reset(histograms_);
   existing_callbacks_.reset(callbacks_);
   existing_ranges_.reset(ranges_);
 
   histograms_ = new HistogramMap;
   callbacks_ = new CallbackMap;
   ranges_ = new RangesMap;
 
-  if (VLOG_IS_ON(1))
+  InitLogOnShutdownWithoutLock();
+}
+
+void StatisticsRecorder::InitLogOnShutdownWithoutLock() {
+  if (!vlog_initialized_ && VLOG_IS_ON(1)) {
+    vlog_initialized_ = true;
     AtExitManager::RegisterCallback(&DumpHistogramsToVlog, this);
+  }
 }
 
 // static
 void StatisticsRecorder::Reset() {
   // If there's no lock then there is nothing to reset.
   if (!lock_)
     return;
 
   std::unique_ptr<HistogramMap> histograms_deleter;
   std::unique_ptr<CallbackMap> callbacks_deleter;
@@ skipping 23 matching lines @@
 // static
 StatisticsRecorder::HistogramMap* StatisticsRecorder::histograms_ = NULL;
 // static
 StatisticsRecorder::CallbackMap* StatisticsRecorder::callbacks_ = NULL;
 // static
 StatisticsRecorder::RangesMap* StatisticsRecorder::ranges_ = NULL;
 // static
 base::Lock* StatisticsRecorder::lock_ = NULL;
 
 }  // namespace base