IPC: Add attachment brokering support to the message header.

ipc/ipc_channel.cc

 // Copyright (c) 2012 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 "ipc/ipc_channel.h"
 
 #include <limits>
 
 #include "base/atomic_sequence_num.h"
 #include "base/rand_util.h"
@@ skipping 23 matching lines @@
   int process_id = -1;
 #else
   int process_id = base::GetCurrentProcId();
 #endif
   return base::StringPrintf("%d.%u.%d",
       process_id,
       g_last_id.GetNext(),
       base::RandInt(0, std::numeric_limits<int32>::max()));
 }
 
+Channel::OutputElement::OutputElement(Message* message)
+    : message_(message), buffer_(nullptr), length_(0) {}
+
+Channel::OutputElement::OutputElement(const char* buffer, size_t length)
+    : message_(nullptr), buffer_(buffer), length_(length) {}
+
+Channel::OutputElement::~OutputElement() {
+  if (message_)

[Tom Sepez, 2015/08/17 18:29:39]

no need to test before delete.  just delete them.
You might consider using a scoped_ptr here instead to indicate ownership.

[erikchen, 2015/08/18 05:59:46]

Done on both counts. 

+    delete message_;
+  if (buffer_)
+    delete buffer_;
+}
+
+size_t Channel::OutputElement::size() {
+  if (message_)
+    return message_->size();
+  return length_;
+}
+
+const void* Channel::OutputElement::data() {
+  if (message_)
+    return message_->data();
+  return buffer_;
+}
+
 }  // namespace IPC