Remove uses of base::hash_map from //chrome

chrome/browser/sync_file_system/subtree_set.h

 // Copyright 2014 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 CHROME_BROWSER_SYNC_FILE_SYSTEM_SUBTREE_SET_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_SUBTREE_SET_H_
 
 #include <stddef.h>
 
+#include <unordered_map>
+
 #include "base/containers/hash_tables.h"
 #include "base/files/file_path.h"
 
 namespace base {
 class FilePath;
 }  // namespace base
 
 namespace sync_file_system {
 
 // Stores disjoint subtrees of a directory tree.
@@ skipping 22 matching lines @@
   struct Node {
     bool contained_as_subtree_root;
     size_t number_of_subtrees_below;
 
     Node();
     Node(bool contained_as_subtree_root,
          size_t number_of_subtrees_below);
   };
 
   typedef base::FilePath::StringType StringType;
-  typedef base::hash_map<StringType, Node> Subtrees;
+  typedef std::unordered_map<StringType, Node> Subtrees;
 
   // Contains the root of subtrees and all upward node to root.
   // Each subtree root has |contained_as_subtree_root| flag true.
   Subtrees inclusive_ancestors_of_subtree_roots_;
 };
 
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_SUBTREE_SET_H_