[usb_gadget p01] Functions for encoding HID descriptors.

tools/usb_gadget/usb_descriptors_test.py

 #!/usr/bin/python
 # 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.
 
 import unittest
 
+import hid_constants
 import usb_descriptors
 
 
 class DescriptorWithField(usb_descriptors.Descriptor):
   pass
 
 DescriptorWithField.AddField('bField', 'B')
 
 
 class DescriptorWithDefault(usb_descriptors.Descriptor):
@@ skipping 170 matching lines @@
         bmAttributes=0xC0,
         MaxPower=100)
     configuration_desc.AddInterface(interface_desc)
     self.assertEquals([interface_desc], configuration_desc.GetInterfaces())
     encoded_configuration = ('\x09\x02\x19\x00\x01\x01\x00\xC0\x64' +
                              encoded_interface)
     self.assertEquals(configuration_desc.Encode(), encoded_configuration)
 
   def test_encode_hid_descriptor(self):
     hid_desc = usb_descriptors.HidDescriptor()
-    hid_desc.AddDescriptor(0x22, 0x80)
-    hid_desc.AddDescriptor(0x23, 0x60)
+    hid_desc.AddDescriptor(hid_constants.DescriptorType.REPORT, 0x80)
+    hid_desc.AddDescriptor(hid_constants.DescriptorType.PHYSICAL, 0x60)
     encoded_desc = '\x0C\x21\x11\x01\x00\x02\x22\x80\x00\x23\x60\x00'
     self.assertEquals(hid_desc.Encode(), encoded_desc)
 
   def test_print_hid_descriptor(self):
     hid_desc = usb_descriptors.HidDescriptor()
-    hid_desc.AddDescriptor(0x22, 0x80)
-    hid_desc.AddDescriptor(0x23, 0x60)
+    hid_desc.AddDescriptor(hid_constants.DescriptorType.REPORT, 0x80)
+    hid_desc.AddDescriptor(hid_constants.DescriptorType.PHYSICAL, 0x60)
     string = str(hid_desc)
     self.assertIn('0x22', string)
     self.assertIn('0x23', string)
 
 
 if __name__ == '__main__':
   unittest.main()