Persist setup metrics and have Chrome report them during UMA upload.

base/metrics/histogram_snapshot_manager.h

Index: base/metrics/histogram_snapshot_manager.h
diff --git a/base/metrics/histogram_snapshot_manager.h b/base/metrics/histogram_snapshot_manager.h
index 3010a6d703bf3f67bca9dde01c9f6f87a5e7fb5f..5d6889ba02739272264e697fa79ee5b29f488891 100644
--- a/base/metrics/histogram_snapshot_manager.h
+++ b/base/metrics/histogram_snapshot_manager.h
@@ -9,6 +9,7 @@
 
 #include <map>
 #include <string>
+#include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
@@ -61,9 +62,13 @@ class BASE_EXPORT HistogramSnapshotManager {
   // until FinishDeltas() completes. PrepareOnce() works the same
   // but assumes there were no previous logged values and no future deltas
   // will be created (and thus can work on read-only histograms).
+  // Use Prepare*TakingOwnership() if it is desireable to have this class
+  // automatically delete the histogram once it is "finished".
   void StartDeltas();
   void PrepareDelta(HistogramBase* histogram);
+  void PrepareDeltaTakingOwnership(scoped_ptr<HistogramBase> histogram);
   void PrepareOnce(const HistogramBase* histogram);
+  void PrepareOnceTakingOwnership(scoped_ptr<const HistogramBase> histogram);
   void FinishDeltas();
 
  private:
@@ -98,7 +103,8 @@ class BASE_EXPORT HistogramSnapshotManager {
   // Capture and hold samples from a histogram. This does all the heavy
   // lifting for PrepareDelta() and PrepareOnce().
   void PrepareSamples(const HistogramBase* histogram,
-                      scoped_ptr<HistogramSamples> samples);
+                      scoped_ptr<HistogramSamples> samples,
+                      bool take_ownership);
 
   // Try to detect and fix count inconsistency of logged samples.
   void InspectLoggedSamplesInconsistency(
@@ -109,6 +115,10 @@ class BASE_EXPORT HistogramSnapshotManager {
   // by the hash of the histogram name.
   std::map<uint64_t, SampleInfo> known_histograms_;
 
+  // Collection of histograms of which ownership has been passed to this
+  // object. They will be deleted by FinishDeltas().
+  std::vector<scoped_ptr<const HistogramBase>> owned_histograms_;
+
   // Indicates if deltas are currently being prepared.
   bool preparing_deltas_;