Use container::back() and container::pop_back() for content.

content/browser/speech/endpointer/energy_endpointer.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.
 //
 // To know more about the algorithm used and the original code which this is
 // based of, see
 // https://wiki.corp.google.com/twiki/bin/view/Main/ChromeGoogleCodeXRef
 
 #include "content/browser/speech/endpointer/energy_endpointer.h"
 
@@ skipping 80 matching lines @@
 }
 
 int64_t EnergyEndpointer::HistoryRing::EndTime() const {
   int ind = insertion_index_ - 1;
   if (ind < 0)
     ind = decision_points_.size() - 1;
   return decision_points_[ind].time_us;
 }
 
 float EnergyEndpointer::HistoryRing::RingSum(float duration_sec) {
-  if (!decision_points_.size())
+  if (decision_points_.empty())
     return 0.0;
 
   int64_t sum_us = 0;
   int ind = insertion_index_ - 1;
   if (ind < 0)
     ind = decision_points_.size() - 1;
   int64_t end_us = decision_points_[ind].time_us;
   bool is_on = decision_points_[ind].decision;
   int64_t start_us =
       end_us - static_cast<int64_t>(0.5 + (1.0e6 * duration_sec));
@@ skipping 258 matching lines @@
       decision_threshold_ = params_.min_decision_threshold();
   }
 }
 
 EpStatus EnergyEndpointer::Status(int64_t* status_time) const {
   *status_time = history_->EndTime();
   return status_;
 }
 
 }  // namespace content