Adding a new message type to the Mojo channel.

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 {
 namespace edk {
 
 #pragma pack(push, 1)
 
 enum BrokerMessageType : uint32_t {
   INIT,
   BUFFER_REQUEST,
   BUFFER_RESPONSE,
 };
 
 struct BrokerMessageHeader {
   BrokerMessageType type;
   uint32_t padding;
 };
 
-static_assert(sizeof(BrokerMessageHeader) % kChannelMessageAlignment == 0,
+static_assert(IsAlignedForChannelMessage(sizeof(BrokerMessageHeader)),
               "Invalid header size.");
 
 struct BufferRequestData {
   uint32_t size;
 };
 
 #if defined(OS_WIN)
 struct InitData {
   // NOTE: InitData in the payload is followed by string16 data with exactly
   // |pipe_name_length| wide characters (i.e., |pipe_name_length|*2 bytes.)
@@ skipping 34 matching lines @@
       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_