[Sync] Replace typedef with using.

components/sync/base/enum_set.h

 // 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.
 
 #ifndef COMPONENTS_SYNC_BASE_ENUM_SET_H_
 #define COMPONENTS_SYNC_BASE_ENUM_SET_H_
 
 #include <bitset>
 #include <cstddef>
 #include <string>
@@ skipping 23 matching lines @@
 // std::bitset<> with stronger type enforcement, more descriptive
 // member function names, and an iterator interface.
 //
 // If you're working with enums with a small number of possible values
 // (say, fewer than 64), you can efficiently pass around an EnumSet
 // for that enum around by value.
 
 template <typename E, E MinEnumValue, E MaxEnumValue>
 class EnumSet {
  public:
-  typedef E EnumType;
+  using EnumType = E;
   static const E kMinValue = MinEnumValue;
   static const E kMaxValue = MaxEnumValue;
   static const size_t kValueCount = kMaxValue - kMinValue + 1;
   static_assert(kMinValue < kMaxValue, "min value must be less than max value");
 
  private:
   // Declaration needed by Iterator.
-  typedef std::bitset<kValueCount> EnumBitSet;
+  using EnumBitSet = std::bitset<kValueCount>;
 
  public:
   // Iterator is a forward-only read-only iterator for EnumSet.  Its
   // interface is deliberately distinct from an STL iterator as its
   // semantics are substantially different.
   //
   // Example usage:
   //
   // for (EnumSet<...>::Iterator it = enums.First(); it.Good(); it.Inc()) {
   //   Process(it.Get());
@@ skipping 191 matching lines @@
 
 template <typename E, E Min, E Max>
 EnumSet<E, Min, Max> Difference(EnumSet<E, Min, Max> set1,
                                 EnumSet<E, Min, Max> set2) {
   return EnumSet<E, Min, Max>(set1.enums_ & ~set2.enums_);
 }
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_BASE_ENUM_SET_H_