Extracted UsbService as interface.

components/usb_service/usb_interface.cc

 // 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.
 
 #include "components/usb_service/usb_interface.h"
 
 #include "base/logging.h"
 #include "third_party/libusb/src/libusb/libusb.h"
 
 namespace usb_service {
@@ skipping 131 matching lines @@
 scoped_refptr<const UsbInterfaceAltSettingDescriptor>
 UsbInterfaceDescriptor::GetAltSetting(size_t index) const {
   return new UsbInterfaceAltSettingDescriptor(config_,
                                               &interface_->altsetting[index]);
 }
 
 UsbConfigDescriptor::UsbConfigDescriptor(PlatformUsbConfigDescriptor config)
     : config_(config) {
 }
 
+// TODO(zvorygin): Used for tests only. Should be removed when
+// all interfaces are extracted properly.
+UsbConfigDescriptor::UsbConfigDescriptor() {
+  config_ = NULL;
+}
+
 UsbConfigDescriptor::~UsbConfigDescriptor() {
   if (config_ != NULL) {
     libusb_free_config_descriptor(config_);
     config_ = NULL;
   }
 }
 
 size_t UsbConfigDescriptor::GetNumInterfaces() const {
   return config_->bNumInterfaces;
 }
 
 scoped_refptr<const UsbInterfaceDescriptor> UsbConfigDescriptor::GetInterface(
     size_t index) const {
   return new UsbInterfaceDescriptor(this, &config_->interface[index]);
 }
 
 }  // namespace usb_service