Fixing a Dr. memory failure in the remoting unit tests.

remoting/host/security_key/remote_security_key_message_reader_impl.cc

Index: remoting/host/security_key/remote_security_key_message_reader_impl.cc
diff --git a/remoting/host/security_key/remote_security_key_message_reader_impl.cc b/remoting/host/security_key/remote_security_key_message_reader_impl.cc
index 2eb441856aa102ddf8b88b9201c03364a1ea223a..0431742ff77d8c2d8210b5bfbc3c91458ae39a22 100644
--- a/remoting/host/security_key/remote_security_key_message_reader_impl.cc
+++ b/remoting/host/security_key/remote_security_key_message_reader_impl.cc
@@ -34,9 +34,8 @@ RemoteSecurityKeyMessageReaderImpl::RemoteSecurityKeyMessageReaderImpl(
 RemoteSecurityKeyMessageReaderImpl::~RemoteSecurityKeyMessageReaderImpl() {
   DCHECK(main_task_runner_->RunsTasksOnCurrentThread());
 
-  // In order to ensure the reader thread is stopped cleanly, we close the
-  // stream it is blocking on and then wait for the thread to exit.
-  read_stream_.Close();
+  // In order to ensure the reader thread is stopped cleanly, we want to stop
+  // the thread before the task runners and weak pointers are invalidated.
   reader_thread_.Stop();
 }