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

net/dns/host_resolver_impl.h

Index: net/dns/host_resolver_impl.h
diff --git a/net/dns/host_resolver_impl.h b/net/dns/host_resolver_impl.h
index 1ca8a8f9ebdc84c77ee25e96591557497c74c9cc..be019a1d416ffa454dc64785df3374cd7bd95cff 100644
--- a/net/dns/host_resolver_impl.h
+++ b/net/dns/host_resolver_impl.h
@@ -14,7 +14,7 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/strings/string_piece.h"
-#include "base/threading/non_thread_safe.h"
+#include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "net/base/net_export.h"
@@ -61,7 +61,6 @@ class NetLogWithSource;
 // Jobs are ordered in the queue based on their priority and order of arrival.
 class NET_EXPORT HostResolverImpl
     : public HostResolver,
-      NON_EXPORTED_BASE(public base::NonThreadSafe),
       public NetworkChangeNotifier::IPAddressObserver,
       public NetworkChangeNotifier::ConnectionTypeObserver,
       public NetworkChangeNotifier::DNSObserver {
@@ -382,6 +381,8 @@ class NET_EXPORT HostResolverImpl
   PersistCallback persist_callback_;
   base::OneShotTimer persist_timer_;
 
+  THREAD_CHECKER(thread_checker_);
+
   base::WeakPtrFactory<HostResolverImpl> weak_ptr_factory_;
 
   base::WeakPtrFactory<HostResolverImpl> probe_weak_ptr_factory_;