Connect SparseHistogram with the rest of stats system

chrome/test/base/uma_histogram_helper.cc

 // Copyright (c) 2012 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 "chrome/test/base/uma_histogram_helper.h"
 
 #include "base/bind.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/test/test_timeouts.h"
 #include "chrome/test/base/ui_test_utils.h"
@@ skipping 14 matching lines @@
       // set to be longer than the normal browser test timeout so that it will
       // be prempted by the normal timeout.
       TestTimeouts::action_max_timeout()*2);
   content::RunMessageLoop();
 }
 
 void UMAHistogramHelper::ExpectUniqueSample(
     const std::string& name,
     base::HistogramBase::Sample sample,
     base::HistogramBase::Count expected_count) {
-  base::Histogram* histogram = base::StatisticsRecorder::FindHistogram(name);
-  EXPECT_NE(static_cast<base::Histogram*>(NULL), histogram)
+  base::HistogramBase* histogram =
+      base::StatisticsRecorder::FindHistogram(name);
+  EXPECT_NE(static_cast<base::HistogramBase*>(NULL), histogram)
       << "Histogram \"" << name << "\" does not exist.";
 
   if (histogram) {
     scoped_ptr<base::HistogramSamples> samples(histogram->SnapshotSamples());
     CheckBucketCount(name, sample, expected_count, *samples);
     CheckTotalCount(name, expected_count, *samples);
   }
 }
 
 void UMAHistogramHelper::ExpectTotalCount(
     const std::string& name,
     base::HistogramBase::Count count) {
-  base::Histogram* histogram = base::StatisticsRecorder::FindHistogram(name);
-  EXPECT_NE(static_cast<base::Histogram*>(NULL), histogram)
+  base::HistogramBase* histogram =
+      base::StatisticsRecorder::FindHistogram(name);
+  EXPECT_NE(static_cast<base::HistogramBase*>(NULL), histogram)
       << "Histogram \"" << name << "\" does not exist.";
 
   if (histogram) {
     scoped_ptr<base::HistogramSamples> samples(histogram->SnapshotSamples());
     CheckTotalCount(name, count, *samples);
   }
 }
 
 void UMAHistogramHelper::FetchCallback() {
   MessageLoopForUI::current()->Quit();
@@ skipping 12 matching lines @@
 
 void UMAHistogramHelper::CheckTotalCount(
     const std::string& name,
     base::HistogramBase::Count expected_count,
     base::HistogramSamples& samples) {
   EXPECT_EQ(expected_count, samples.TotalCount())
       << "Histogram \"" << name
       << "\" does not have the right total number of samples ("
       << expected_count << ").";
 }