[mojo-edk] Invalidate message handle when rewrite fails

mojo/edk/system/node_channel.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 "mojo/edk/system/node_channel.h"
 
 #include <cstring>
 #include <limits>
 #include <sstream>
 
@@ skipping 169 matching lines @@
   base::AutoLock lock(channel_lock_);
   if (channel_) {
     channel_->ShutDown();
     channel_ = nullptr;
   }
 }
 
 void NodeChannel::SetRemoteProcessHandle(base::ProcessHandle process_handle) {
   DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
   base::AutoLock lock(remote_process_handle_lock_);
+  CHECK_NE(remote_process_handle_, base::GetCurrentProcessHandle());
   remote_process_handle_ = process_handle;
 }
 
 bool NodeChannel::HasRemoteProcessHandle() {
   base::AutoLock lock(remote_process_handle_lock_);
   return remote_process_handle_ != base::kNullProcessHandle;
 }
 
 base::ProcessHandle NodeChannel::CopyRemoteProcessHandle() {
   base::AutoLock lock(remote_process_handle_lock_);
@@ skipping 520 matching lines @@
 
   base::AutoLock lock(channel_lock_);
   if (!channel_)
     DLOG(ERROR) << "Dropping message on closed channel.";
   else
     channel_->Write(std::move(message));
 }
 
 }  // namespace edk
 }  // namespace mojo