Remove std::string histogram name from HistogramBase object.

base/metrics/statistics_recorder_unittest.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 "base/metrics/statistics_recorder.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <vector>
@@ skipping 59 matching lines @@
     DCHECK(!statistics_recorder_);
     StatisticsRecorder::UninitializeForTesting();
     statistics_recorder_ = StatisticsRecorder::CreateTemporaryForTesting();
   }
 
   void UninitializeStatisticsRecorder() {
     statistics_recorder_.reset();
     StatisticsRecorder::UninitializeForTesting();
   }
 
-  Histogram* CreateHistogram(const std::string& name,
+  Histogram* CreateHistogram(const char* name,
                              HistogramBase::Sample min,
                              HistogramBase::Sample max,
                              size_t bucket_count) {
     BucketRanges* ranges = new BucketRanges(bucket_count + 1);
     Histogram::InitializeBucketRanges(min, max, ranges);
     const BucketRanges* registered_ranges =
         StatisticsRecorder::RegisterOrDeleteDuplicateRanges(ranges);
     return new Histogram(name, min, max, registered_ranges);
   }
 
@@ skipping 618 matching lines @@
   histogram->Add(3);
   histogram->Add(5);
   StatisticsRecorder::ImportProvidedHistograms();
   snapshot = found->SnapshotSamples();
   EXPECT_EQ(3, snapshot->TotalCount());
   EXPECT_EQ(2, snapshot->GetCount(3));
   EXPECT_EQ(1, snapshot->GetCount(5));
 }
 
 }  // namespace base