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

mojo/edk/system/node_channel.cc

Index: mojo/edk/system/node_channel.cc
diff --git a/mojo/edk/system/node_channel.cc b/mojo/edk/system/node_channel.cc
index 1608a3d6b5f7cb6908b9323790ecd219f2514d92..5452cc96ef131526bcc199203e0f7892b1014276 100644
--- a/mojo/edk/system/node_channel.cc
+++ b/mojo/edk/system/node_channel.cc
@@ -208,6 +208,13 @@ void NodeChannel::ShutDown() {
   }
 }
 
+void NodeChannel::LeakHandleOnShutdown() {
+  base::AutoLock lock(channel_lock_);
+  if (channel_) {
+    channel_->LeakHandle();
+  }
+}
+
 void NodeChannel::NotifyBadMessage(const std::string& error) {
   if (!process_error_callback_.is_null())
     process_error_callback_.Run("Received bad user message: " + error);