Log histograms on shutdown when verbose logging is on

base/metrics/statistics_recorder.cc

Index: base/metrics/statistics_recorder.cc
diff --git a/base/metrics/statistics_recorder.cc b/base/metrics/statistics_recorder.cc
index 1279bae6e0b60a26cd8e43d4a29ec12f684efc2a..a53f8f2a3c82f9a52f5e84a0930d158af0e189f8 100644
--- a/base/metrics/statistics_recorder.cc
+++ b/base/metrics/statistics_recorder.cc
@@ -338,6 +338,14 @@ StatisticsRecorder::HistogramIterator StatisticsRecorder::end() {
 }
 
 // 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)
@@ -482,8 +490,14 @@ StatisticsRecorder::StatisticsRecorder() {
   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