Use interface associations to check function permissions.

device/usb/usb_device_handle_impl.h

 // Copyright 2014 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 DEVICE_USB_USB_DEVICE_HANDLE_IMPL_H_
 #define DEVICE_USB_USB_DEVICE_HANDLE_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 14 matching lines @@
 class TaskRunner;
 }
 
 namespace net {
 class IOBuffer;
 }
 
 namespace device {
 
 struct EndpointMapValue {
-  int interface_number;
-  UsbTransferType transfer_type;
+  const UsbInterfaceDescriptor* interface;
+  const UsbEndpointDescriptor* endpoint;
 };
 
 class UsbContext;
 struct UsbConfigDescriptor;
 class UsbDeviceImpl;
 
 typedef libusb_device_handle* PlatformUsbDeviceHandle;
 typedef libusb_iso_packet_descriptor* PlatformUsbIsoPacketDescriptor;
 typedef libusb_transfer* PlatformUsbTransferHandle;
 
@@ skipping 37 matching lines @@
       const std::vector<uint32_t>& packet_lengths,
       unsigned int timeout,
       const IsochronousTransferCallback& callback) override;
 
   void GenericTransfer(UsbEndpointDirection direction,
                        uint8_t endpoint_number,
                        scoped_refptr<net::IOBuffer> buffer,
                        size_t length,
                        unsigned int timeout,
                        const TransferCallback& callback) override;
-  bool FindInterfaceByEndpoint(uint8_t endpoint_address,
-                               uint8_t* interface_number) override;
+  const UsbInterfaceDescriptor* FindInterfaceByEndpoint(
+      uint8_t endpoint_address) override;
 
  protected:
   friend class UsbDeviceImpl;
 
   // This constructor is called by UsbDeviceImpl.
   UsbDeviceHandleImpl(
       scoped_refptr<UsbContext> context,
       scoped_refptr<UsbDeviceImpl> device,
       PlatformUsbDeviceHandle handle,
       scoped_refptr<base::SequencedTaskRunner> blocking_task_runner);
@@ skipping 104 matching lines @@
   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(UsbDeviceHandleImpl);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_USB_USB_DEVICE_HANDLE_IMPL_H_