Avoid initializing child processes with an invalid parent pipe

mojo/edk/system/core.cc

 // Copyright 2013 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/core.h"
 
 #include <string.h>
 
 #include <utility>
 
@@ skipping 69 matching lines @@
   return handles_.GetDispatcher(handle);
 }
 
 void Core::AddChild(base::ProcessHandle process_handle,
                     ScopedPlatformHandle platform_handle) {
   GetNodeController()->ConnectToChild(process_handle,
                                       std::move(platform_handle));
 }
 
 void Core::InitChild(ScopedPlatformHandle platform_handle) {
-  GetNodeController()->ConnectToParent(std::move(platform_handle));
+  if (platform_handle.is_valid())
+    GetNodeController()->ConnectToParent(std::move(platform_handle));
 }
 
 MojoHandle Core::AddDispatcher(scoped_refptr<Dispatcher> dispatcher) {
   base::AutoLock lock(handles_lock_);
   return handles_.AddDispatcher(dispatcher);
 }
 
 bool Core::AddDispatchersFromTransit(
     const std::vector<Dispatcher::DispatcherInTransit>& dispatchers,
     MojoHandle* handles) {
@@ skipping 668 matching lines @@
     scoped_ptr<NodeController> node_controller) {
   // It's OK to leak this reference. At this point we know the IO loop is still
   // running, and we know the NodeController will observe its eventual
   // destruction. This tells the NodeController to delete itself when that
   // happens.
   node_controller.release()->DestroyOnIOThreadShutdown();
 }
 
 }  // namespace edk
 }  // namespace mojo