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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef BASE_METRICS_HISTOGRAM_FLATTENER_H_
      6 #define BASE_METRICS_HISTOGRAM_FLATTENER_H_
      7 
      8 #include <map>
      9 #include <string>
     10 
     11 #include "base/macros.h"
     12 #include "base/metrics/histogram.h"
     13 
     14 namespace base {
     15 
     16 class HistogramSamples;
     17 
     18 // HistogramFlattener is an interface used by HistogramSnapshotManager, which
     19 // handles the logistics of gathering up available histograms for recording.
     20 // The implementors handle the exact lower level recording mechanism, or
     21 // error report mechanism.
     22 class BASE_EXPORT HistogramFlattener {
     23  public:
     24   virtual void RecordDelta(const HistogramBase& histogram,
     25                            const HistogramSamples& snapshot) = 0;
     26 
     27   // Will be called each time a type of Inconsistency is seen on a histogram,
     28   // during inspections done internally in HistogramSnapshotManager class.
     29   virtual void InconsistencyDetected(HistogramBase::Inconsistency problem) = 0;
     30 
     31   // Will be called when a type of Inconsistency is seen for the first time on
     32   // a histogram.
     33   virtual void UniqueInconsistencyDetected(
     34       HistogramBase::Inconsistency problem) = 0;
     35 
     36   // Will be called when the total logged sample count of a histogram
     37   // differs from the sum of logged sample count in all the buckets.  The
     38   // argument |amount| is the non-zero discrepancy.
     39   virtual void InconsistencyDetectedInLoggedCount(int amount) = 0;
     40 
     41  protected:
     42   HistogramFlattener() {}
     43   virtual ~HistogramFlattener() {}
     44 
     45  private:
     46   DISALLOW_COPY_AND_ASSIGN(HistogramFlattener);
     47 };
     48 
     49 }  // namespace base
     50 
     51 #endif  // BASE_METRICS_HISTOGRAM_FLATTENER_H_
     52