Log histograms on shutdown when verbose logging is on

base/metrics/statistics_recorder.h

 // 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.
 
 // StatisticsRecorder holds all Histograms and BucketRanges that are used by
 // Histograms in the system. It provides a general place for
 // Histograms/BucketRanges to register, and supports a global API for accessing
 // (i.e., dumping, or graphing) the data.
 
 #ifndef BASE_METRICS_STATISTICS_RECORDER_H_
@@ skipping 112 matching lines @@
 
   // ClearCallback clears any callback set on the histogram referred to by
   // |histogram_name|. This method is thread safe.
   static void ClearCallback(const std::string& histogram_name);
 
   // FindCallback retrieves the callback for the histogram referred to by
   // |histogram_name|, or a null callback if no callback exists for this
   // histogram. This method is thread safe.
   static OnSampleCallback FindCallback(const std::string& histogram_name);
 
+  // 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();
+
+  static bool VLogInitializedForTesting();
+
   // Clears all of the known histograms and resets static variables to a
   // state that allows a new initialization.
   static void ResetForTesting();
 
   // 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.
   static void ForgetHistogramForTesting(base::StringPiece name);
 
  private:
   // We keep a map of callbacks to histograms, so that as histograms are
   // created, we can set the callback properly.
   typedef std::map<std::string, OnSampleCallback> CallbackMap;
 
   // We keep all |bucket_ranges_| in a map, from checksum to a list of
   // |bucket_ranges_|.  Checksum is calculated from the |ranges_| in
   // |bucket_ranges_|.
   typedef std::map<uint32_t, std::list<const BucketRanges*>*> RangesMap;
 
   friend struct DefaultLazyInstanceTraits<StatisticsRecorder>;
   friend class HistogramBaseTest;
   friend class HistogramSnapshotManagerTest;
   friend class HistogramTest;
   friend class JsonPrefStoreTest;
   friend class SharedHistogramTest;
   friend class SparseHistogramTest;
   friend class StatisticsRecorderTest;
+  friend class StatisticsRecorderLoggingTestBase;
   FRIEND_TEST_ALL_PREFIXES(HistogramDeltaSerializationTest,
                            DeserializeHistogramAndAddSamples);
 
   // The constructor just initializes static members. Usually client code should
   // use Initialize to do this. But in test code, you can friend this class and
   // call destructor/constructor to get a clean StatisticsRecorder.
   StatisticsRecorder();
   ~StatisticsRecorder();
 
+  void InitLogOnShutdownWithoutLock();
+
   static void Reset();
   static void DumpHistogramsToVlog(void* instance);
 
   static HistogramMap* histograms_;
   static CallbackMap* callbacks_;
   static RangesMap* ranges_;
 
   // Lock protects access to above maps.
   static base::Lock* lock_;
 
   DISALLOW_COPY_AND_ASSIGN(StatisticsRecorder);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_STATISTICS_RECORDER_H_