[UMA] Remove redundant bucket_count variable from base::Histogram.

base/metrics/sparse_histogram.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/sparse_histogram.h"
 
 #include "base/metrics/sample_map.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/pickle.h"
 #include "base/strings/stringprintf.h"
@@ skipping 21 matching lines @@
   DCHECK_EQ(SPARSE_HISTOGRAM, histogram->GetHistogramType());
   return histogram;
 }
 
 SparseHistogram::~SparseHistogram() {}
 
 HistogramType SparseHistogram::GetHistogramType() const {
   return SPARSE_HISTOGRAM;
 }
 
-bool SparseHistogram::HasConstructionArguments(Sample minimum,
-                                               Sample maximum,
-                                               size_t bucket_count) const {
+bool SparseHistogram::HasConstructionArguments(
+    Sample expected_minimum,
+    Sample expected_maximum,
+    size_t expected_bucket_count) const {
   // SparseHistogram never has min/max/bucket_count limit.
   return false;
 }
 
 void SparseHistogram::Add(Sample value) {
   base::AutoLock auto_lock(lock_);
   samples_.Accumulate(value, 1);
 }
 
 scoped_ptr<HistogramSamples> SparseHistogram::SnapshotSamples() const {
@@ skipping 114 matching lines @@
                                        std::string* output) const {
   StringAppendF(output,
                 "Histogram: %s recorded %d samples",
                 histogram_name().c_str(),
                 total_count);
   if (flags() & ~kHexRangePrintingFlag)
     StringAppendF(output, " (flags = 0x%x)", flags() & ~kHexRangePrintingFlag);
 }
 
 }  // namespace base