Adding UseCounter specific for extensions

base/test/histogram_tester.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/test/histogram_tester.h"
 
 #include <stddef.h>
 
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_samples.h"
@@ skipping 77 matching lines @@
     for (auto it = snapshot->Iterator(); !it->Done(); it->Next()) {
       HistogramBase::Sample sample;
       HistogramBase::Count count;
       it->Get(&sample, nullptr, &count);
       samples.push_back(Bucket(sample, count));
     }
   }
   return samples;
 }
 
+HistogramBase::Count HistogramTester::GetBucketCount(
+    const std::string& name,
+    HistogramBase::Sample sample) const {
+  HistogramBase* histogram = StatisticsRecorder::FindHistogram(name);
+  EXPECT_NE(nullptr, histogram)
+      << "Histogram \"" << name << "\" does not exist.";
+  HistogramBase::Count count = 0;
+  if (histogram) {
+    std::unique_ptr<HistogramSamples> samples = histogram->SnapshotSamples();
+    GetBucketCountForSamples(name, sample, *samples, &count);
+  }
+  return count;
+}
+
+void HistogramTester::GetBucketCountForSamples(
+    const std::string& name,
+    HistogramBase::Sample sample,
+    const HistogramSamples& samples,
+    HistogramBase::Count* count) const {
+  *count = samples.GetCount(sample);
+  auto histogram_data = histograms_snapshot_.find(name);
+  if (histogram_data != histograms_snapshot_.end())
+    *count -= histogram_data->second->GetCount(sample);
+}
+
 HistogramTester::CountsMap HistogramTester::GetTotalCountsForPrefix(
     const std::string& prefix) const {
   EXPECT_TRUE(prefix.find('.') != std::string::npos)
       << "|prefix| ought to contain at least one period, to avoid matching too"
       << " many histograms.";
 
   // Find candidate matches by using the logic built into GetSnapshot().
   StatisticsRecorder::Histograms candidate_matches;
   StatisticsRecorder::GetSnapshot(prefix, &candidate_matches);
 
@@ skipping 32 matching lines @@
   auto original_samples_it = histograms_snapshot_.find(histogram_name);
   if (original_samples_it != histograms_snapshot_.end())
     named_samples->Subtract(*original_samples_it->second.get());
   return named_samples;
 }
 
 void HistogramTester::CheckBucketCount(const std::string& name,
                                        HistogramBase::Sample sample,
                                        HistogramBase::Count expected_count,
                                        const HistogramSamples& samples) const {
-  int actual_count = samples.GetCount(sample);
-  auto histogram_data = histograms_snapshot_.find(name);
-  if (histogram_data != histograms_snapshot_.end())
-    actual_count -= histogram_data->second->GetCount(sample);
+  int actual_count;
+  GetBucketCountForSamples(name, sample, samples, &actual_count);
 
   EXPECT_EQ(expected_count, actual_count)
       << "Histogram \"" << name
       << "\" does not have the right number of samples (" << expected_count
       << ") in the expected bucket (" << sample << "). It has (" << actual_count
       << ").";
 }
 
 void HistogramTester::CheckTotalCount(const std::string& name,
                                       HistogramBase::Count expected_count,
@@ skipping 11 matching lines @@
 
 bool Bucket::operator==(const Bucket& other) const {
   return min == other.min && count == other.count;
 }
 
 void PrintTo(const Bucket& bucket, std::ostream* os) {
   *os << "Bucket " << bucket.min << ": " << bucket.count;
 }
 
 }  // namespace base