Adding ThreadChecker validation to d'tors for host classes

remoting/host/security_key/security_key_extension_session.cc

Index: remoting/host/security_key/security_key_extension_session.cc
diff --git a/remoting/host/security_key/security_key_extension_session.cc b/remoting/host/security_key/security_key_extension_session.cc
index f637981bbf44f013cb4326c9a9024cd4e8175fae..966204dc75a8867ae055a9f6c56f7a04f3d86ab0 100644
--- a/remoting/host/security_key/security_key_extension_session.cc
+++ b/remoting/host/security_key/security_key_extension_session.cc
@@ -75,7 +75,9 @@ SecurityKeyExtensionSession::SecurityKeyExtensionSession(
       file_task_runner);
 }
 
-SecurityKeyExtensionSession::~SecurityKeyExtensionSession() {}
+SecurityKeyExtensionSession::~SecurityKeyExtensionSession() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
 
 // Returns true if the |message| is a Security Key ExtensionMessage.
 // This is done so the host does not pass |message| to other HostExtensions.