Connect SparseHistogram with the rest of stats system

base/metrics/histogram_base.h

Index: base/metrics/histogram_base.h
diff --git a/base/metrics/histogram_base.h b/base/metrics/histogram_base.h
index 729670cf98699e9af4a3215b6494cc62cdd515d0..30e7c2df5594f76f3b2a9c98da4e9120e45dabb7 100644
--- a/base/metrics/histogram_base.h
+++ b/base/metrics/histogram_base.h
@@ -48,6 +48,17 @@ BASE_EXPORT void DeserializeHistogramAndAddSamples(PickleIterator* iter);
 
 ////////////////////////////////////////////////////////////////////////////////
 
+// Histogram data inconsistency types.
+enum BASE_EXPORT HistogramInconsistency {
+  NO_INCONSISTENCIES = 0x0,

[brettw, 2013/02/28 22:56:25]

This creates things named base::COUNT_LOW_ERROR, for example, which isn't
sufficiently unique or self-documenting. Either this should be a member of
HistogramBase or it needs some kind of unique prefix. I'd do the member like it
used to be in Histogram.

[kaiwang, 2013/03/01 00:52:12]

Done.

+  RANGE_CHECKSUM_ERROR = 0x1,
+  BUCKET_ORDER_ERROR = 0x2,
+  COUNT_HIGH_ERROR = 0x4,
+  COUNT_LOW_ERROR = 0x8,
+
+  NEVER_EXCEEDED_VALUE = 0x10
+};
+
 class BASE_EXPORT HistogramBase {
  public:
   typedef int Sample;  // Used for samples.
@@ -103,6 +114,10 @@ class BASE_EXPORT HistogramBase {
   // does not serialize the samples.
   bool SerializeInfo(Pickle* pickle) const;
 
+  // Try to find out data corruption from histogram and the samples.
+  // The returned value is a combination of HistogramInconsistency enum.
+  virtual int FindCorruption(const HistogramSamples& samples) const;
+
   // Snapshot the current complete set of sample data.
   // Override with atomic/locked snapshot if needed.
   virtual scoped_ptr<HistogramSamples> SnapshotSamples() const = 0;