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

chromecast/net/net_util_cast.h

Index: chromecast/net/net_util_cast.h
diff --git a/chromecast/net/net_util_cast.h b/chromecast/net/net_util_cast.h
index 2ec95bbd985a7b15ab6da890c2ccd8ddbfa9a48f..72a980a5a65984d1cb502d3eb375d6758121c1ca 100644
--- a/chromecast/net/net_util_cast.h
+++ b/chromecast/net/net_util_cast.h
@@ -6,14 +6,13 @@
 #define CHROMECAST_NET_NET_UTIL_H_
 
 #include <string>
-
-#include "base/containers/hash_tables.h"
+#include <unordered_set>
 
 namespace chromecast {
 
 // Gets the list of interfaces that should be ignored. The interfaces returned
 // by this function will not be used to connect to the internet.
-base::hash_set<std::string> GetIgnoredInterfaces();
+std::unordered_set<std::string> GetIgnoredInterfaces();
 
 }  // namespace chromecast