Fix a bunch of clang warnings/errors.

base/mach_ipc_mac.h

 // Copyright (c) 2006-2008 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_MACH_IPC_MAC_H_
 #define BASE_MACH_IPC_MAC_H_
 #pragma once
 
 #include <mach/mach.h>
 #include <mach/message.h>
@@ skipping 96 matching lines @@
   }
 
   mach_port_t GetMachPort() const {
     return name;
   }
 
   mach_msg_type_name_t GetDisposition() const {
     return disposition;
   }
 
-  // We're just a simple wrapper for mach_msg_port_descriptor_t
-  // and have the same memory layout
-  operator mach_msg_port_descriptor_t&() {
-    return *this;
-  }
-
   // For convenience
   operator mach_port_t() const {
     return GetMachPort();
   }
 };
 
 //==============================================================================
 // MachMessage: a wrapper for a Mach message
 //  (mach_msg_header_t, mach_msg_body_t, extra data)
 //
@@ skipping 186 matching lines @@
  private:
   mach_port_t   send_port_;
   kern_return_t init_result_;
 
   DISALLOW_COPY_AND_ASSIGN(MachPortSender);
 };
 
 }  // namespace base
 
 #endif // BASE_MACH_IPC_MAC_H_