Update from https://crrev.com/333737

base/metrics/sample_vector.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/sample_vector.h"
 
 #include "base/logging.h"
 #include "base/metrics/bucket_ranges.h"
 
-using std::vector;
-
 namespace base {
 
 typedef HistogramBase::Count Count;
 typedef HistogramBase::Sample Sample;
 
 SampleVector::SampleVector(const BucketRanges* bucket_ranges)
     : counts_(bucket_ranges->bucket_count()),
       bucket_ranges_(bucket_ranges) {
   CHECK_GE(bucket_ranges_->bucket_count(), 1u);
 }
@@ skipping 82 matching lines @@
       under = mid;
     else
       over = mid;
   } while (true);
 
   DCHECK_LE(bucket_ranges_->range(mid), value);
   CHECK_GT(bucket_ranges_->range(mid + 1), value);
   return mid;
 }
 
-SampleVectorIterator::SampleVectorIterator(const vector<Count>* counts,
+SampleVectorIterator::SampleVectorIterator(const std::vector<Count>* counts,
                                            const BucketRanges* bucket_ranges)
     : counts_(counts),
       bucket_ranges_(bucket_ranges),
       index_(0) {
   CHECK_GE(bucket_ranges_->bucket_count(), counts_->size());
   SkipEmptyBuckets();
 }
 
 SampleVectorIterator::~SampleVectorIterator() {}
 
@@ skipping 31 matching lines @@
     return;
 
   while (index_ < counts_->size()) {
     if (subtle::NoBarrier_Load(&(*counts_)[index_]) != 0)
       return;
     index_++;
   }
 }
 
 }  // namespace base