Connect SparseHistogram with the rest of stats system

base/metrics/sparse_histogram.cc

Index: base/metrics/sparse_histogram.cc
diff --git a/base/metrics/sparse_histogram.cc b/base/metrics/sparse_histogram.cc
index c64f7cb1c649dff13de20a8a9ed04e3a320a1973..296c0179ab23ae279e541251843270bd1bc6c473 100644
--- a/base/metrics/sparse_histogram.cc
+++ b/base/metrics/sparse_histogram.cc
@@ -7,6 +7,7 @@
 #include "base/metrics/sample_map.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/pickle.h"
+#include "base/stringprintf.h"

[Ilya Sherman, 2013/02/21 05:36:06]

nit: Doesn't look like this is needed.

[kaiwang, 2013/02/27 04:39:42]

Done.

 #include "base/synchronization/lock.h"
 
 using std::map;
@@ -19,9 +20,16 @@ typedef HistogramBase::Sample Sample;
 
 // static
 HistogramBase* SparseHistogram::FactoryGet(const string& name, int32 flags) {
-  // TODO(kaiwang): Register and get SparseHistogram with StatisticsRecorder.
-  HistogramBase* histogram = new SparseHistogram(name);
-  histogram->SetFlags(flags);
+  HistogramBase* histogram = StatisticsRecorder::FindHistogram(name);
+
+  if (!histogram) {
+    // To avoid racy destruction at shutdown, the following will be leaked.
+    HistogramBase* tentative_histogram = new SparseHistogram(name);
+    tentative_histogram->SetFlags(flags);
+    histogram =
+        StatisticsRecorder::RegisterOrDeleteDuplicate(tentative_histogram);
+  }
+  CHECK_EQ(SPARSE_HISTOGRAM, histogram->GetHistogramType());

[Ilya Sherman, 2013/02/21 05:36:06]

nit: DCHECK_EQ

[kaiwang, 2013/02/27 04:39:42]

This is following histogram.h
Seems this kind of errors are treated as serious enough to CHECK

[Ilya Sherman, 2013/02/28 00:29:56]

They shouldn't be.  It would be good to fix histogram.h as well.

[kaiwang, 2013/02/28 04:58:05]

Done.

   return histogram;
 }