Move mach code shared by Chrome IPC and Mojo to //base/mac.

base/mac/mach_port_util.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 BASE_MAC_MACH_PORT_UTIL_H_
+#define BASE_MAC_MACH_PORT_UTIL_H_
+
+#include <mach/mach.h>
+
+#include "base/base_export.h"
+#include "base/mac/scoped_mach_port.h"
+
+namespace base {
+
+// Sends a Mach port to |dest_port|. Assumes that |dest_port| is a send once
+// right. Takes ownership of |dest_port|.
+BASE_EXPORT kern_return_t SendMachPort(mach_port_t dest_port,
+                                       mach_port_t port_to_send,
+                                       int disposition);
+
+// Receives a Mach port from |port_to_listen_on|, which should have exactly one
+// queued message. Returns |MACH_PORT_NULL| on any error.
+BASE_EXPORT base::mac::ScopedMachSendRight ReceiveMachPort(
+    mach_port_t port_to_listen_on);
+
+// Creates an intermediate Mach port in |task_port| and sends |port_to_insert|
+// as a mach_msg to the intermediate Mach port.
+// |task_port| is the task port of another process.
+// |port_to_insert| must be a send right in the current task's name space.
+// Returns the intermediate port on success, and MACH_PORT_NULL on failure.
+// On failure, if |error_code| is not null, it is set to an error code as
+// defined in IPC::AttachmentBrokerPrivileged::UMAError.

[erikchen, 2016/03/10 17:54:09]

Use an enum here, and have IPC::AttachmentBrokerPrivileged do the conversion
from this enum to the UMA values..

[Anand Mistry (off Chromium), 2016/03/11 00:29:04]

Is this what you had in mind?

[erikchen, 2016/03/11 00:30:56]

yup. still lgtm.

+// This method takes ownership of |port_to_insert|. On success, ownership is
+// passed to the intermediate Mach port.
+BASE_EXPORT mach_port_name_t CreateIntermediateMachPort(
+    mach_port_t task_port,
+    base::mac::ScopedMachSendRight port_to_insert,
+    uint32_t* error_code);
+
+}  // namespace base
+
+#endif  // BASE_MAC_MACH_PORT_UTIL_H_