[Sync] Replace typedef with using.

components/sync/syncable/change_reorder_buffer.cc

 // Copyright 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 "components/sync/syncable/change_reorder_buffer.h"
 
 #include <limits>
 #include <queue>
 #include <set>
 #include <utility>  // for pair<>
@@ skipping 11 matching lines @@
 namespace syncer {
 
 // Traversal provides a way to collect a set of nodes from the syncable
 // directory structure and then traverse them, along with any intermediate
 // nodes, in a top-down fashion, starting from a single common ancestor.  A
 // Traversal starts out empty and is grown by means of the ExpandToInclude
 // method.  Once constructed, the top(), begin_children(), and end_children()
 // methods can be used to explore the nodes in root-to-leaf order.
 class ChangeReorderBuffer::Traversal {
  public:
-  typedef pair<int64_t, int64_t> ParentChildLink;
-  typedef set<ParentChildLink> LinkSet;
+  using ParentChildLink = pair<int64_t, int64_t>;
+  using LinkSet = set<ParentChildLink>;
 
   Traversal() : top_(kInvalidId) {}
 
   // Expand the traversal so that it includes the node indicated by
   // |child_handle|.
   void ExpandToInclude(syncable::BaseTransaction* trans, int64_t child_handle) {
     // If |top_| is invalid, this is the first insertion -- easy.
     if (top_ == kInvalidId) {
       top_ = child_handle;
       return;
@@ skipping 168 matching lines @@
       CHECK(j->first == next);
       to_visit.push(j->second);
     }
   }
 
   *changes = ImmutableChangeRecordList(&changelist);
   return true;
 }
 
 }  // namespace syncer