Support "shared" histograms between processes.

base/metrics/histogram_snapshot_manager_unittest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/metrics/histogram_snapshot_manager.h"
 
 #include <string>
 #include <vector>
 
 #include "base/metrics/histogram_delta_serialization.h"
@@ skipping 45 matching lines @@
   StatisticsRecorder statistics_recorder_;
   HistogramFlattenerDeltaRecorder histogram_flattener_delta_recorder_;
   HistogramSnapshotManager histogram_snapshot_manager_;
 };
 
 TEST_F(HistogramSnapshotManagerTest, PrepareDeltasNoFlagsFilter) {
   // kNoFlags filter should record all histograms.
   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();
   EXPECT_EQ(2U, histograms.size());
   EXPECT_EQ("UmaHistogram", histograms[0]);
   EXPECT_EQ("UmaStabilityHistogram", histograms[1]);
 }
 
 TEST_F(HistogramSnapshotManagerTest, PrepareDeltasUmaHistogramFlagFilter) {
   // Note that kUmaStabilityHistogramFlag includes kUmaTargetedHistogramFlag.
   UMA_HISTOGRAM_ENUMERATION("UmaHistogram", 1, 2);
   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 =
       histogram_flattener_delta_recorder_.GetRecordedDeltaHistogramNames();
   EXPECT_EQ(2U, histograms.size());
   EXPECT_EQ("UmaHistogram", histograms[0]);
   EXPECT_EQ("UmaStabilityHistogram", histograms[1]);
 }
 
 TEST_F(HistogramSnapshotManagerTest,
        PrepareDeltasUmaStabilityHistogramFlagFilter) {
   UMA_HISTOGRAM_ENUMERATION("UmaHistogram", 1, 2);
   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 =
       histogram_flattener_delta_recorder_.GetRecordedDeltaHistogramNames();
   EXPECT_EQ(1U, histograms.size());
   EXPECT_EQ("UmaStabilityHistogram", histograms[0]);
 }
 
 }  // namespace base