[mojo-edk] Simplify multiprocess pipe bootstrap

mojo/edk/system/core.cc

Index: mojo/edk/system/core.cc
diff --git a/mojo/edk/system/core.cc b/mojo/edk/system/core.cc
index aad9541642fcad64ef94c40dc7cfd2ef8feeceae..99978af5fdd6b275260e84dcc643fd38fdeefc33 100644
--- a/mojo/edk/system/core.cc
+++ b/mojo/edk/system/core.cc
@@ -160,14 +160,16 @@ void Core::RequestShutdown(const base::Closure& callback) {
   GetNodeController()->RequestShutdown(on_shutdown);
 }
 
-void Core::CreateMessagePipe(
-    ScopedPlatformHandle platform_handle,
-    const base::Callback<void(ScopedMessagePipeHandle)>& callback) {
-  ports::PortRef port;
-  GetNodeController()->node()->CreateUninitializedPort(&port);
+ScopedMessagePipeHandle Core::CreateMessagePipe(
+    ScopedPlatformHandle platform_handle) {
+  ports::PortRef port0, port1;
+  GetNodeController()->node()->CreatePortPair(&port0, &port1);
+  MojoHandle handle = AddDispatcher(
+    new MessagePipeDispatcher(GetNodeController(), port0,
+                              0x7f7f7f7f7f7f7f7fUL, 0));
   RemoteMessagePipeBootstrap::Create(
-      GetNodeController(), std::move(platform_handle), port,
-      base::Bind(&OnPortConnected, base::Unretained(this), 0, callback, port));
+      GetNodeController(), std::move(platform_handle), port1);
+  return ScopedMessagePipeHandle(MessagePipeHandle(handle));
 }
 
 void Core::CreateParentMessagePipe(