Use interface associations to check function permissions.

device/usb/mojo/type_converters.cc

 // 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.
 
 #include "device/usb/mojo/type_converters.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <map>
@@ skipping 168 matching lines @@
   // interface number.
   std::map<uint8_t, device::usb::InterfaceInfo*> interface_map;
   for (size_t i = 0; i < interfaces.size(); ++i) {
     auto alternate = device::usb::AlternateInterfaceInfo::From(interfaces[i]);
     auto iter = interface_map.find(interfaces[i].interface_number);
     if (iter == interface_map.end()) {
       // This is the first time we're seeing an alternate with this interface
       // number, so add a new InterfaceInfo to the array and map the number.
       auto info = device::usb::InterfaceInfo::New();
       info->interface_number = interfaces[i].interface_number;
+      info->first_interface = interfaces[i].first_interface;
       iter = interface_map
                  .insert(
                      std::make_pair(interfaces[i].interface_number, info.get()))
                  .first;
       infos.push_back(std::move(info));
     }
     iter->second->alternates.push_back(std::move(alternate));
   }
 
   return infos;
@@ skipping 80 matching lines @@
     Convert(const device::UsbDeviceHandle::IsochronousPacket& packet) {
   device::usb::IsochronousPacketPtr info =
       device::usb::IsochronousPacket::New();
   info->length = packet.length;
   info->transferred_length = packet.transferred_length;
   info->status = mojo::ConvertTo<device::usb::TransferStatus>(packet.status);
   return info;
 }
 
 }  // namespace mojo