[mojo-edk] Initialise padding in mojo::edk::BrokerMessageHeader.

mojo/edk/system/broker_messages.h

 // 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.
 
 #ifndef MOJO_EDK_SYSTEM_BROKER_MESSAGES_H_
 #define MOJO_EDK_SYSTEM_BROKER_MESSAGES_H_
 
 #include "mojo/edk/system/channel.h"
 
 namespace mojo {
@@ skipping 23 matching lines @@
 
 template <typename T>
 inline Channel::MessagePtr CreateBrokerMessage(BrokerMessageType type,
                                                size_t num_handles,
                                                T** out_message_data) {
   const size_t message_size = sizeof(BrokerMessageHeader) + sizeof(T);
   Channel::MessagePtr message(new Channel::Message(message_size, num_handles));
   BrokerMessageHeader* header =
       reinterpret_cast<BrokerMessageHeader*>(message->mutable_payload());
   header->type = type;
+  header->padding = 0;
   *out_message_data = reinterpret_cast<T*>(header + 1);
   return message;
 }
 
 inline Channel::MessagePtr CreateBrokerMessage(
     BrokerMessageType type,
     size_t num_handles,
     std::nullptr_t** dummy_out_data) {
   Channel::MessagePtr message(
       new Channel::Message(sizeof(BrokerMessageHeader), num_handles));
   BrokerMessageHeader* header =
       reinterpret_cast<BrokerMessageHeader*>(message->mutable_payload());
   header->type = type;
+  header->padding = 0;
   return message;
 }
 
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_BROKER_MESSAGES_H_