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..12d126dcc9c1b61cd82cee1313e07145ef08e207 100644
--- a/base/metrics/histogram_base.h
+++ b/base/metrics/histogram_base.h
@@ -70,6 +70,17 @@ class BASE_EXPORT HistogramBase {
     kHexRangePrintingFlag = 0x8000,
   };
 
+  // Histogram data inconsistency types.
+  enum Inconsistency {
+    NO_INCONSISTENCIES = 0x0,
+    RANGE_CHECKSUM_ERROR = 0x1,
+    BUCKET_ORDER_ERROR = 0x2,
+    COUNT_HIGH_ERROR = 0x4,
+    COUNT_LOW_ERROR = 0x8,
+
+    NEVER_EXCEEDED_VALUE = 0x10
+  };
+
   explicit HistogramBase(const std::string& name);
   virtual ~HistogramBase();
 
@@ -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 Inconsistency 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;