Deprecate NonThreadSafe in net/ in favor of SequenceChecker/ThreadChecker.

net/dns/host_cache.h

Index: net/dns/host_cache.h
diff --git a/net/dns/host_cache.h b/net/dns/host_cache.h
index 37cf204e3ccb653aa3d642ad560a4ed361d7d5d9..379d825a16821e3dde8203b6bdb9bb07e1dd02d1 100644
--- a/net/dns/host_cache.h
+++ b/net/dns/host_cache.h
@@ -14,7 +14,7 @@
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
-#include "base/threading/non_thread_safe.h"
+#include "base/sequence_checker.h"
 #include "base/time/time.h"
 #include "net/base/address_family.h"
 #include "net/base/address_list.h"
@@ -25,7 +25,7 @@
 namespace net {
 
 // Cache used by HostResolver to map hostnames to their resolved result.
-class NET_EXPORT HostCache : NON_EXPORTED_BASE(public base::NonThreadSafe) {
+class NET_EXPORT HostCache {
  public:
   struct Key {
     Key(const std::string& hostname, AddressFamily address_family,
@@ -199,6 +199,8 @@ class NET_EXPORT HostCache : NON_EXPORTED_BASE(public base::NonThreadSafe) {
   int network_changes_;
   EvictionCallback eviction_callback_;
 
+  SEQUENCE_CHECKER(sequence_checker_);
+
   DISALLOW_COPY_AND_ASSIGN(HostCache);
 };