[counting_allocator] Chrome changes.

base/containers/flat_set.h

 // Copyright 2017 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.
 
 #ifndef BASE_CONTAINERS_FLAT_SET_H_
 #define BASE_CONTAINERS_FLAT_SET_H_
 
 #include <algorithm>
 #include <functional>
 #include <utility>
@@ skipping 67 matching lines @@
 // but it seems to be a quadratic algorithm. For now we do not implement this
 // method.
 // TODO(dyaroshev): research an algorithm for range insertion crbug.com/682249.
 
 template <class Key, class Compare = std::less<Key>>
 // Meets the requirements of Container, AssociativeContainer,
 // ReversibleContainer.
 // Requires: Key is Movable, Compare is a StrictWeakOrdering on Key.
 class flat_set {
  private:
-  using underlying_type = std::vector<Key>;
+  using underlying_type = std::vector<Key, std::counting_allocator<Key, std::allocation_group::base_flat_set>>;
 
  public:
   // --------------------------------------------------------------------------
   // Types.
   //
   using key_type = Key;
   using key_compare = Compare;
   using value_type = Key;
   using value_compare = Compare;
 
@@ skipping 564 matching lines @@
 // Erases all elements that match predicate. It has O(size) complexity.
 template <typename Key, typename Compare, typename Predicate>
 void EraseIf(base::flat_set<Key, Compare>& container, Predicate pred) {
   container.erase(std::remove_if(container.begin(), container.end(), pred),
                   container.end());
 }
 
 }  // namespace  base
 
 #endif  // BASE_CONTAINERS_FLAT_SET_H_