Revert of Remove IPC::BrokerableAttachment.

ipc/handle_attachment_win.cc

Index: ipc/handle_attachment_win.cc
diff --git a/ipc/handle_attachment_win.cc b/ipc/handle_attachment_win.cc
index 9249a5a069c65802824a74ea289072d63d5a2b0c..53d589bc8f182e1ca8f86da3ebf0d04f1eae342b 100644
--- a/ipc/handle_attachment_win.cc
+++ b/ipc/handle_attachment_win.cc
@@ -28,13 +28,24 @@
                                          FromWire from_wire)
     : handle_(handle), permissions_(HandleWin::INVALID), owns_handle_(true) {}
 
+HandleAttachmentWin::HandleAttachmentWin(const WireFormat& wire_format)
+    : handle_(LongToHandle(wire_format.handle)),
+      permissions_(wire_format.permissions),
+      owns_handle_(true) {}
+
 HandleAttachmentWin::~HandleAttachmentWin() {
   if (handle_ != INVALID_HANDLE_VALUE && owns_handle_)
     ::CloseHandle(handle_);
 }
 
-MessageAttachment::Type HandleAttachmentWin::GetType() const {
-  return Type::WIN_HANDLE;
+HandleAttachmentWin::BrokerableType HandleAttachmentWin::GetBrokerableType()
+    const {
+  return WIN_HANDLE;
+}
+
+HandleAttachmentWin::WireFormat HandleAttachmentWin::GetWireFormat(
+    const base::ProcessId& destination) const {
+  return WireFormat(HandleToLong(handle_), destination, permissions_);
 }
 
 }  // namespace internal