[mojo-edk] Simplify multiprocess pipe bootstrap

mojo/edk/system/remote_message_pipe_bootstrap.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/remote_message_pipe_bootstrap.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/macros.h"
 #include "base/thread_task_runner_handle.h"
@@ skipping 13 matching lines @@
   // The port name of the sender's local bootstrap port.
   ports::PortName port_name;
 };
 
 }  // namespace
 
 // static
 void RemoteMessagePipeBootstrap::Create(
     NodeController* node_controller,
     ScopedPlatformHandle platform_handle,
-    const ports::PortRef& port,
-    const base::Closure& callback) {
+    const ports::PortRef& port) {
   if (node_controller->io_task_runner()->RunsTasksOnCurrentThread()) {
     // Owns itself.
-    new RemoteMessagePipeBootstrap(node_controller, std::move(platform_handle),
-                                   port, callback);
+    new RemoteMessagePipeBootstrap(
+        node_controller, std::move(platform_handle), port);
   } else {
     node_controller->io_task_runner()->PostTask(
         FROM_HERE,
         base::Bind(&RemoteMessagePipeBootstrap::Create,
                    base::Unretained(node_controller),
-                   base::Passed(&platform_handle), port, callback));
+                   base::Passed(&platform_handle), port));
   }
 }
 
 RemoteMessagePipeBootstrap::~RemoteMessagePipeBootstrap() {
   DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
   base::MessageLoop::current()->RemoveDestructionObserver(this);
   if (channel_)
     channel_->ShutDown();
 }
 
 RemoteMessagePipeBootstrap::RemoteMessagePipeBootstrap(
     NodeController* node_controller,
     ScopedPlatformHandle platform_handle,
-    const ports::PortRef& port,
-    const base::Closure& callback)
+    const ports::PortRef& port)
     : node_controller_(node_controller),
       local_port_(port),
-      callback_(callback),
       io_task_runner_(base::ThreadTaskRunnerHandle::Get()),
       channel_(Channel::Create(this, std::move(platform_handle),
                                io_task_runner_)) {
   base::MessageLoop::current()->AddDestructionObserver(this);
   channel_->Start();
 
   Channel::MessagePtr message(new Channel::Message(sizeof(BootstrapData), 0));
   BootstrapData* data = static_cast<BootstrapData*>(message->mutable_payload());
   data->node_name = node_controller_->name();
   data->port_name = local_port_.name();
@@ skipping 38 matching lines @@
     return;
   }
 
   if (payload_size != sizeof(BootstrapData)) {
     DLOG(ERROR) << "Invalid bootstrap payload.";
     ShutDown();
     return;
   }
 
   peer_info_received_ = true;
-  node_controller_->ConnectToRemotePort(
-      local_port_, data->node_name, data->port_name, callback_);
+
+  // We need to choose one side to initiate the port merge. It doesn't matter
+  // who does it as long as they don't both try. Simple solution: pick the one
+  // with the "smaller" port name.
+  if (local_port_.name() < data->port_name) {
+    node_controller_->node()->MergePorts(local_port_, data->node_name,
+                                         data->port_name);
+  }
 
   // Send another ping to the other end to trigger shutdown. This may race with
   // the other end sending its own ping, but it doesn't matter. Whoever wins
   // will cause the other end to tear down, and the ensuing channel error will
   // in turn clean up the remaining end.
 
   Channel::MessagePtr message(new Channel::Message(0, 0));
   channel_->Write(std::move(message));
 }
 
 void RemoteMessagePipeBootstrap::OnChannelError() {
   DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
   ShutDown();
 }
 
 void RemoteMessagePipeBootstrap::ShutDownNow() {
   delete this;
 }
 
 }  // namespace edk
 }  // namespace mojo