Connect SparseHistogram with the rest of stats system

base/metrics/histogram_base.cc

Index: base/metrics/histogram_base.cc
diff --git a/base/metrics/histogram_base.cc b/base/metrics/histogram_base.cc
index 403303a9cbecedb2708ffcee36fb2e64e3fd2cfb..835a05b56efd4ad1087e1363cd4757c1f44f7899 100644
--- a/base/metrics/histogram_base.cc
+++ b/base/metrics/histogram_base.cc
@@ -100,6 +100,11 @@ bool HistogramBase::SerializeInfo(Pickle* pickle) const {
   return SerializeInfoImpl(pickle);
 }
 
+int HistogramBase::FindCorruption(const HistogramSamples& samples) const {
+  // Not supported by default.
+  return NO_INCONSISTENCIES;
+}
+
 void HistogramBase::WriteJSON(std::string* output) const {
   Count count;
   scoped_ptr<ListValue> buckets(new ListValue());