Log histograms on shutdown when verbose logging is on

base/metrics/statistics_recorder.h

Index: base/metrics/statistics_recorder.h
diff --git a/base/metrics/statistics_recorder.h b/base/metrics/statistics_recorder.h
index 6c436c292e6987027276e0cdee49e60787ba1280..37b20a2a806d46e88efaacaa82fcd8b195e7745f 100644
--- a/base/metrics/statistics_recorder.h
+++ b/base/metrics/statistics_recorder.h
@@ -165,6 +165,12 @@ class BASE_EXPORT StatisticsRecorder {
   // Returns the number of known histograms.
   static size_t GetHistogramCount();
 
+  // Initializes logging histograms with --v=1. Safe to call several times.
+  // Is called from ctor but for browser it seems that it is more useful to
+  // start logging after statistics recorder, so we need to init log-on-shutdown
+  // later.
+  static void InitLogOnShutdown();
+
   // Removes a histogram from the internal set of known ones. This can be
   // necessary during testing persistent histograms where the underlying
   // memory is being released.
@@ -211,6 +217,10 @@ class BASE_EXPORT StatisticsRecorder {
   std::unique_ptr<CallbackMap> existing_callbacks_;
   std::unique_ptr<RangesMap> existing_ranges_;
 
+  bool vlog_initialized_ = false;
+
+  void InitLogOnShutdownWithoutLock();

[Alexei Svitkine (slow), 2016/06/29 14:24:47]

Nit: Add a comment.

+
   static void Reset();
   static void DumpHistogramsToVlog(void* instance);