Support "shared" histograms between processes.

base/metrics/histogram_snapshot_manager_unittest.cc

Index: base/metrics/histogram_snapshot_manager_unittest.cc
diff --git a/base/metrics/histogram_snapshot_manager_unittest.cc b/base/metrics/histogram_snapshot_manager_unittest.cc
index e9e7398bca9fa9761263c8878b780430c3c1f233..20b324eb18fc107d0ce8a696064da5fb75d1ce5a 100644
--- a/base/metrics/histogram_snapshot_manager_unittest.cc
+++ b/base/metrics/histogram_snapshot_manager_unittest.cc
@@ -63,8 +63,9 @@ TEST_F(HistogramSnapshotManagerTest, PrepareDeltasNoFlagsFilter) {
   UMA_HISTOGRAM_ENUMERATION("UmaHistogram", 1, 2);
   UMA_STABILITY_HISTOGRAM_ENUMERATION("UmaStabilityHistogram", 1, 2);
 
-  histogram_snapshot_manager_.PrepareDeltas(HistogramBase::kNoFlags,
-                                            HistogramBase::kNoFlags);
+  histogram_snapshot_manager_.PrepareDeltas(
+      StatisticsRecorder::begin(false), StatisticsRecorder::end(),
+      HistogramBase::kNoFlags, HistogramBase::kNoFlags);
 
   const std::vector<std::string>& histograms =
       histogram_flattener_delta_recorder_.GetRecordedDeltaHistogramNames();
@@ -79,6 +80,7 @@ TEST_F(HistogramSnapshotManagerTest, PrepareDeltasUmaHistogramFlagFilter) {
   UMA_STABILITY_HISTOGRAM_ENUMERATION("UmaStabilityHistogram", 1, 2);
 
   histogram_snapshot_manager_.PrepareDeltas(
+      StatisticsRecorder::begin(false), StatisticsRecorder::end(),
       HistogramBase::kNoFlags, HistogramBase::kUmaTargetedHistogramFlag);
 
   const std::vector<std::string>& histograms =
@@ -94,6 +96,7 @@ TEST_F(HistogramSnapshotManagerTest,
   UMA_STABILITY_HISTOGRAM_ENUMERATION("UmaStabilityHistogram", 1, 2);
 
   histogram_snapshot_manager_.PrepareDeltas(
+      StatisticsRecorder::begin(false), StatisticsRecorder::end(),
       HistogramBase::kNoFlags, HistogramBase::kUmaStabilityHistogramFlag);
 
   const std::vector<std::string>& histograms =