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

net/disk_cache/blockfile/backend_impl_v3.h

Index: net/disk_cache/blockfile/backend_impl_v3.h
diff --git a/net/disk_cache/blockfile/backend_impl_v3.h b/net/disk_cache/blockfile/backend_impl_v3.h
index d4ab00aee61465a3f1ad8b53229551f64d2b4f78..df51c2137afd9b10f3b8735026b25523e4e0983b 100644
--- a/net/disk_cache/blockfile/backend_impl_v3.h
+++ b/net/disk_cache/blockfile/backend_impl_v3.h
@@ -9,8 +9,7 @@
 
 #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"
@@ -199,7 +198,7 @@
 
  private:
   friend class EvictionV3;
-  using EntriesMap = std::unordered_map<CacheAddr, EntryImplV3*>;
+  typedef base::hash_map<CacheAddr, EntryImplV3*> EntriesMap;
   class IteratorImpl;
   class NotImplementedIterator;
   class Worker;