Adding ThreadChecker validation to d'tors for host classes

remoting/host/linux/certificate_watcher.cc

 // Copyright 2016 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.
 
 #include "remoting/host/linux/certificate_watcher.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/files/file_util.h"
 #include "base/hash.h"
@@ skipping 80 matching lines @@
     scoped_refptr<base::SingleThreadTaskRunner> caller_task_runner,
     base::FilePath cert_watch_path,
     base::TimeDelta read_delay)
     : watcher_(watcher),
       caller_task_runner_(caller_task_runner),
       cert_watch_path_(cert_watch_path),
       delay_(read_delay) {
   thread_checker_.DetachFromThread();
 }
 
-CertDbContentWatcher::~CertDbContentWatcher() {}
+CertDbContentWatcher::~CertDbContentWatcher() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
 
 void CertDbContentWatcher::StartWatching() {
   DCHECK(!cert_watch_path_.empty());
   DCHECK(thread_checker_.CalledOnValidThread());
 
   file_watcher_.reset(new base::FilePathWatcher());
 
   // Initialize hash value.
   current_hash_ = ComputeHash();
 
@@ skipping 142 matching lines @@
   if (inhibit_mode_) {
     restart_pending_ = true;
     return;
   }
 
   VLOG(1) << "Certificate was updated. Calling restart...";
   restart_action_.Run();
 }
 
 }  // namespace remoting