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..e4cff7e7947ad3e404045452516c8f527bd259dd 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,
+  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 int32 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;