Replace deprecated base::NonThreadSafe in jingle in favor of SequenceChecker.

jingle/notifier/base/weak_xmpp_client.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // A thin wrapper around buzz::XmppClient that exposes weak pointers
 // so that users know when the buzz::XmppClient becomes invalid to use
 // (not necessarily only at destruction time).
 
 #ifndef JINGLE_NOTIFIER_BASE_WEAK_XMPP_CLIENT_H_
 #define JINGLE_NOTIFIER_BASE_WEAK_XMPP_CLIENT_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
-#include "base/threading/non_thread_safe.h"
+#include "base/sequence_checker.h"
 #include "third_party/libjingle_xmpp/xmpp/xmppclient.h"
 
 namespace rtc {
 class TaskParent;
 }  // namespace
 
 namespace notifier {
 
 // buzz::XmppClient's destructor isn't marked virtual, but it inherits
 // from rtc::Task, whose destructor *is* marked virtual, so we
 // can safely inherit from it.
-class WeakXmppClient : public buzz::XmppClient, public base::NonThreadSafe {
+class WeakXmppClient : public buzz::XmppClient {
  public:
   explicit WeakXmppClient(rtc::TaskParent* parent);
 
   ~WeakXmppClient() override;
 
   // Returns a weak pointer that is invalidated when the XmppClient
   // becomes invalid to use.
   base::WeakPtr<WeakXmppClient> AsWeakPtr();
 
   // Invalidates all weak pointers to this object.  (This method is
   // necessary as calling Abort() does not always lead to Stop() being
   // called, so it's not a reliable way to cause an invalidation.)
   void Invalidate();
 
  protected:
   void Stop() override;
 
  private:
+  SEQUENCE_CHECKER(sequence_checker_);
+
   // We use our own WeakPtrFactory instead of inheriting from
   // SupportsWeakPtr since we want to invalidate in other places
   // besides the destructor.
   base::WeakPtrFactory<WeakXmppClient> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WeakXmppClient);
 };
 
 }  // namespace notifier
 
 #endif  // JINGLE_NOTIFIER_BASE_WEAK_XMPP_CLIENT_H_