Fix Mojo broker crash on Windows.

mojo/edk/system/broker_messages.h

 // Copyright 2015 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.
 
 #ifndef MOJO_EDK_SYSTEM_BROKER_MESSAGES_H_
 #define MOJO_EDK_SYSTEM_BROKER_MESSAGES_H_
 
 #include <stdint.h>
 
 #include "base/compiler_specific.h"
@@ skipping 35 matching lines @@
 
 #endif
 
 // Route id used for messages between ChildBroker and ChildBrokerHost.
 const uint64_t kBrokerRouteId = 1;
 
 // Multiplexing related messages. They are all asynchronous messages.
 // They are sent over RawChannel.
 enum MultiplexMessages {
   // Messages from child to parent.
+
+  // Tells the parent that the given pipe id has been bound to a
+  // MessagePipeDispatcher in the child process. The parent will then respond
+  // with either PEER_PIPE_CONNECTED or PEER_DIED when the other side is also
+  // bound.
   CONNECT_MESSAGE_PIPE = 0,
+  // Tells the parent to remove its bookkeeping for the given peer id since
+  // another MessagePipeDispatcher has connected to the pipe in the same
+  // process.
   CANCEL_CONNECT_MESSAGE_PIPE,
 
+
   // Messages from parent to child.
+
+  // Tells the child to open a channel to a given process. This will be followed
+  // by a PEER_PIPE_CONNECTED connecting a message pipe from the child process
+  // to the given process over the new channel.
   CONNECT_TO_PROCESS,
+
+  // Connect a given message pipe to another process.
   PEER_PIPE_CONNECTED,
+
+  // Informs the child that the other end of the message pipe is in a process
+  // that died.
+  PEER_DIED,
 };
 
 struct ConnectMessagePipeMessage {
   // CONNECT_MESSAGE_PIPE or CANCEL_CONNECT_MESSAGE_PIPE
   MultiplexMessages type;
   uint64_t pipe_id;
 };
 
 struct ConnectToProcessMessage {
   MultiplexMessages type;  // CONNECT_TO_PROCESS
   base::ProcessId process_id;
   // Also has an attached platform handle.
 };
 
 struct PeerPipeConnectedMessage {
   MultiplexMessages type;  // PEER_PIPE_CONNECTED
   uint64_t pipe_id;
   base::ProcessId process_id;
 };
 
+struct PeerDiedMessage {
+  MultiplexMessages type;  // PEER_DIED
+  uint64_t pipe_id;
+};
+
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_BROKER_MESSAGES_H_