Report histogram creation results.

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 45 matching lines @@
     bool operator!=(const HistogramIterator& rhs) const {
       return iter_ != rhs.iter_;
     }
     HistogramBase* operator*() { return iter_->second; }
 
    private:
     HistogramMap::iterator iter_;
     const bool include_persistent_;
   };
 
+  ~StatisticsRecorder();
+
   // Initializes the StatisticsRecorder system. Safe to call multiple times.
   static void Initialize();
 
   // Find out if histograms can now be registered into our list.
   static bool IsActive();
 
   // Register, or add a new histogram to the collection of statistics. If an
   // identically named histogram is already registered, then the argument
   // |histogram| will deleted.  The returned value is always the registered
   // histogram (either the argument, or the pre-existing registered histogram).
@@ skipping 47 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);
 
+  // Returns the number of known histograms.
+  static size_t GetHistogramCount();
+
   // 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:
@@ skipping 12 matching lines @@
   friend class HistogramTest;
   friend class JsonPrefStoreTest;
   friend class SharedHistogramTest;
   friend class SparseHistogramTest;
   friend class StatisticsRecorderTest;
   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.
+  // call the constructor to get a clean StatisticsRecorder.
   StatisticsRecorder();
-  ~StatisticsRecorder();
 
   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_