Use interface associations to check function permissions.

device/usb/mock_usb_device_handle.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 DEVICE_USB_MOCK_USB_DEVICE_HANDLE_H_
 #define DEVICE_USB_MOCK_USB_DEVICE_HANDLE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 46 matching lines @@
                     const std::vector<uint32_t>& packet_lengths,
                     unsigned int timeout,
                     const IsochronousTransferCallback& callback));
   MOCK_METHOD6(GenericTransfer,
                void(UsbEndpointDirection direction,
                     uint8_t endpoint,
                     scoped_refptr<net::IOBuffer> buffer,
                     size_t length,
                     unsigned int timeout,
                     const TransferCallback& callback));
-  MOCK_METHOD2(FindInterfaceByEndpoint,
-               bool(uint8_t endpoint_address, uint8_t* interface_number));
+  MOCK_METHOD1(FindInterfaceByEndpoint,
+               const UsbInterfaceDescriptor*(uint8_t endpoint_address));
 
  private:
   ~MockUsbDeviceHandle() override;
 
   UsbDevice* device_;
 };
 
 }  // namespace device
 
 #endif  // DEVICE_USB_MOCK_USB_DEVICE_HANDLE_H_