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

net/base/network_change_notifier_linux.h

Index: net/base/network_change_notifier_linux.h
diff --git a/net/base/network_change_notifier_linux.h b/net/base/network_change_notifier_linux.h
index 1a82b590972d06b97202e2ff89b30cb4406723b6..48bda6bdd4a0fce1ee694a357e2579a9a423e954 100644
--- a/net/base/network_change_notifier_linux.h
+++ b/net/base/network_change_notifier_linux.h
@@ -5,9 +5,8 @@
 #ifndef NET_BASE_NETWORK_CHANGE_NOTIFIER_LINUX_H_
 #define NET_BASE_NETWORK_CHANGE_NOTIFIER_LINUX_H_
 
-#include <unordered_set>
-
 #include "base/compiler_specific.h"
+#include "base/containers/hash_tables.h"
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "net/base/net_export.h"
@@ -25,7 +24,7 @@
   // interfaces used to connect to the internet can cause critical network
   // changed signals to be lost allowing incorrect stale state to persist.
   explicit NetworkChangeNotifierLinux(
-      const std::unordered_set<std::string>& ignored_interfaces);
+      const base::hash_set<std::string>& ignored_interfaces);
 
  private:
   class Thread;