Reland 'Convert //net and //chromecast to std::unordered_*'

net/disk_cache/blockfile/backend_impl.h

Index: net/disk_cache/blockfile/backend_impl.h
diff --git a/net/disk_cache/blockfile/backend_impl.h b/net/disk_cache/blockfile/backend_impl.h
index cbc854bf591662b1a54ecc821ab13d52100d8619..5ecd3072ae708d9a2fc7b6691e61b4a2971f4358 100644
--- a/net/disk_cache/blockfile/backend_impl.h
+++ b/net/disk_cache/blockfile/backend_impl.h
@@ -9,7 +9,8 @@
 
 #include <stdint.h>
 
-#include "base/containers/hash_tables.h"
+#include <unordered_map>
+
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
@@ -293,7 +294,7 @@ class NET_EXPORT_PRIVATE BackendImpl : public Backend {
   void OnExternalCacheHit(const std::string& key) override;
 
  private:
-  typedef base::hash_map<CacheAddr, EntryImpl*> EntriesMap;
+  using EntriesMap = std::unordered_map<CacheAddr, EntryImpl*>;
   class IteratorImpl;
 
   // Creates a new backing file for the cache index.