Always leak the Mojo parent pipe handle on child process shutdown.

mojo/edk/system/node_controller.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_controller.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/bind.h"
@@ skipping 352 matching lines @@
   {
     base::AutoLock lock(parent_lock_);
     DCHECK(parent_name_ == ports::kInvalidNodeName);
 
     // At this point we don't know the parent's name, so we can't yet insert it
     // into our |peers_| map. That will happen as soon as we receive an
     // AcceptChild message from them.
     bootstrap_parent_channel_ =
         NodeChannel::Create(this, std::move(platform_handle), io_task_runner_,
                             ProcessErrorCallback());
+    // Prevent the parent pipe handle from being closed on shutdown. Pipe
+    // closure is used by the parent to detect the child process has exited.
+    // Relying on message pipes to be closed is not enough because the parent
+    // may see the message pipe closure before the child is dead, causing the
+    // child process to be unexpectedly SIGKILL'd.
+    bootstrap_parent_channel_->LeakHandleOnShutdown();
   }
   bootstrap_parent_channel_->Start();
 }
 
 scoped_refptr<NodeChannel> NodeController::GetPeerChannel(
     const ports::NodeName& name) {
   base::AutoLock lock(peers_lock_);
   auto it = peers_.find(name);
   if (it == peers_.end())
     return nullptr;
@@ skipping 738 matching lines @@
     shutdown_callback_flag_.Set(false);
   }
 
   DCHECK(!callback.is_null());
 
   callback.Run();
 }
 
 }  // namespace edk
 }  // namespace mojo