IPC: Remove unnecessary conversions of BrokerableAttachment.

ipc/attachment_broker_privileged_mac.h

 // Copyright 2015 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 IPC_ATTACHMENT_BROKER_PRIVILEGED_MAC_H_
 #define IPC_ATTACHMENT_BROKER_PRIVILEGED_MAC_H_
 
 #include <mach/mach.h>
 
 #include "base/gtest_prod_util.h"
@@ skipping 37 matching lines @@
 //
 // For the rest of this file, and the corresponding implementation file, R will
 // be called the "intermediate Mach port" and M3 the "final Mach port".
 class IPC_EXPORT AttachmentBrokerPrivilegedMac
     : public AttachmentBrokerPrivileged {
  public:
   explicit AttachmentBrokerPrivilegedMac(base::PortProvider* port_provider);
   ~AttachmentBrokerPrivilegedMac() override;
 
   // IPC::AttachmentBroker overrides.
-  bool SendAttachmentToProcess(BrokerableAttachment* attachment,
-                               base::ProcessId destination_process) override;
+  bool SendAttachmentToProcess(
+      const scoped_refptr<IPC::BrokerableAttachment>& attachment,
+      base::ProcessId destination_process) override;
 
   // IPC::Listener overrides.
   bool OnMessageReceived(const Message& message) override;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(AttachmentBrokerPrivilegedMacMultiProcessTest,
                            InsertRight);
   FRIEND_TEST_ALL_PREFIXES(AttachmentBrokerPrivilegedMacMultiProcessTest,
                            InsertSameRightTwice);
   FRIEND_TEST_ALL_PREFIXES(AttachmentBrokerPrivilegedMacMultiProcessTest,
@@ skipping 54 matching lines @@
 
   // The port provider must live at least as long as the AttachmentBroker.
   base::PortProvider* port_provider_;
 
   DISALLOW_COPY_AND_ASSIGN(AttachmentBrokerPrivilegedMac);
 };
 
 }  // namespace IPC
 
 #endif  // IPC_ATTACHMENT_BROKER_PRIVILEGED_MAC_H_