Revert of Convert device::UsbConfigDescriptor and friends to structs.

device/usb/usb_device.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_H_
 #define DEVICE_USB_USB_DEVICE_H_
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 
 namespace device {
 
 class UsbDeviceHandle;
-struct UsbConfigDescriptor;
+class UsbConfigDescriptor;
 
 // A UsbDevice object represents a detected USB device, providing basic
 // information about it. For further manipulation of the device, a
 // UsbDeviceHandle must be created from Open() method.
 class UsbDevice : public base::RefCountedThreadSafe<UsbDevice> {
  public:
   // Accessors to basic information.
   uint16 vendor_id() const { return vendor_id_; }
   uint16 product_id() const { return product_id_; }
   uint32 unique_id() const { return unique_id_; }
@@ skipping 11 matching lines @@
   // Creates a UsbDeviceHandle for further manipulation.
   // Blocking method. Must be called on FILE thread.
   virtual scoped_refptr<UsbDeviceHandle> Open() = 0;
 
   // Explicitly closes a device handle. This method will be automatically called
   // by the destructor of a UsbDeviceHandle as well.
   // Closing a closed handle is a safe
   // Blocking method. Must be called on FILE thread.
   virtual bool Close(scoped_refptr<UsbDeviceHandle> handle) = 0;
 
-  // Gets the UsbConfigDescriptor for the active device configuration.
+  // Lists the interfaces provided by the device and fills the given
+  // UsbConfigDescriptor.
   // Blocking method. Must be called on FILE thread.
-  virtual const UsbConfigDescriptor& GetConfiguration() = 0;
+  virtual scoped_refptr<UsbConfigDescriptor> ListInterfaces() = 0;
 
  protected:
   UsbDevice(uint16 vendor_id, uint16 product_id, uint32 unique_id)
       : vendor_id_(vendor_id), product_id_(product_id), unique_id_(unique_id) {}
 
   virtual ~UsbDevice() {}
 
  private:
   friend class base::RefCountedThreadSafe<UsbDevice>;
 
   const uint16 vendor_id_;
   const uint16 product_id_;
   const uint32 unique_id_;
 
   DISALLOW_COPY_AND_ASSIGN(UsbDevice);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_USB_USB_DEVICE_H_