Revert of Convert //net and //chromecast to std::unordered_*

net/disk_cache/blockfile/backend_impl.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.
 
 // See net/disk_cache/disk_cache.h for the public interface of the cache.
 
 #ifndef NET_DISK_CACHE_BLOCKFILE_BACKEND_IMPL_H_
 #define NET_DISK_CACHE_BLOCKFILE_BACKEND_IMPL_H_
 
 #include <stdint.h>
 
-#include <unordered_map>
-
+#include "base/containers/hash_tables.h"
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/timer/timer.h"
 #include "net/disk_cache/blockfile/block_files.h"
 #include "net/disk_cache/blockfile/eviction.h"
 #include "net/disk_cache/blockfile/in_flight_backend_io.h"
 #include "net/disk_cache/blockfile/rankings.h"
 #include "net/disk_cache/blockfile/stats.h"
 #include "net/disk_cache/blockfile/stress_support.h"
@@ skipping 263 matching lines @@
   // entries on the cache only if the cache is not modified while the
   // enumeration is taking place. Significantly altering the entry pointed by
   // the iterator (for example, deleting the entry) will invalidate the
   // iterator. Performing operations on an entry that modify the entry may
   // result in loops in the iteration, skipped entries or similar.
   scoped_ptr<Iterator> CreateIterator() override;
   void GetStats(StatsItems* stats) override;
   void OnExternalCacheHit(const std::string& key) override;
 
  private:
-  using EntriesMap = std::unordered_map<CacheAddr, EntryImpl*>;
+  typedef base::hash_map<CacheAddr, EntryImpl*> EntriesMap;
   class IteratorImpl;
 
   // Creates a new backing file for the cache index.
   bool CreateBackingStore(disk_cache::File* file);
   bool InitBackingStore(bool* file_created);
   void AdjustMaxCacheSize(int table_len);
 
   bool InitStats();
   void StoreStats();
 
@@ skipping 100 matching lines @@
   base::WaitableEvent done_;  // Signals the end of background work.
   scoped_refptr<TraceObject> trace_object_;  // Initializes internal tracing.
   base::WeakPtrFactory<BackendImpl> ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BackendImpl);
 };
 
 }  // namespace disk_cache
 
 #endif  // NET_DISK_CACHE_BLOCKFILE_BACKEND_IMPL_H_