Revert of Remove IPC::BrokerableAttachment.

ipc/ipc_message.cc

Index: ipc/ipc_message.cc
diff --git a/ipc/ipc_message.cc b/ipc/ipc_message.cc
index f5e9ac7a8b807cd04842aa8139a5b9b8cfb0b9ee..008401f14f358c620a7e6a206bb9fb969fa63220 100644
--- a/ipc/ipc_message.cc
+++ b/ipc/ipc_message.cc
@@ -166,14 +166,18 @@
 
 bool Message::WriteAttachment(
     scoped_refptr<base::Pickle::Attachment> attachment) {
+  bool brokerable;
   size_t index;
   bool success = attachment_set()->AddAttachment(
       make_scoped_refptr(static_cast<MessageAttachment*>(attachment.get())),
-      &index);
+      &index, &brokerable);
   DCHECK(success);
 
   // NOTE: If you add more data to the pickle, make sure to update
   // PickleSizer::AddAttachment.
+
+  // Write the type of descriptor.
+  WriteBool(brokerable);
 
   // Write the index of the descriptor so that we don't have to
   // keep the current descriptor as extra decoding state when deserialising.
@@ -185,6 +189,10 @@
 bool Message::ReadAttachment(
     base::PickleIterator* iter,
     scoped_refptr<base::Pickle::Attachment>* attachment) const {
+  bool brokerable;
+  if (!iter->ReadBool(&brokerable))
+    return false;
+
   int index;
   if (!iter->ReadInt(&index))
     return false;
@@ -193,7 +201,9 @@
   if (!attachment_set)
     return false;
 
-  *attachment = attachment_set->GetAttachmentAt(index);
+  *attachment = brokerable
+                    ? attachment_set->GetBrokerableAttachmentAt(index)
+                    : attachment_set->GetNonBrokerableAttachmentAt(index);
 
   return nullptr != attachment->get();
 }
@@ -202,4 +212,13 @@
   return attachment_set_.get() && !attachment_set_->empty();
 }
 
+bool Message::HasMojoHandles() const {
+  return attachment_set_.get() && attachment_set_->num_mojo_handles() > 0;
+}
+
+bool Message::HasBrokerableAttachments() const {
+  return attachment_set_.get() &&
+         attachment_set_->num_brokerable_attachments() > 0;
+}
+
 }  // namespace IPC