Add device path enumeration to the new Windows USB backend.

device/usb/usb_service_impl.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.
 
 #include "device/usb/usb_service.h"
 
 #include <stddef.h>
 
 #include <map>
 #include <queue>
@@ skipping 16 matching lines @@
 
 namespace base {
 class SequencedTaskRunner;
 }
 
 namespace device {
 
 typedef struct libusb_device* PlatformUsbDevice;
 typedef struct libusb_context* PlatformUsbContext;
 
+class UsbDeviceImpl;

[scheib, 2017/02/14 19:40:05]

You don't use this, at least in this patch.

[Reilly Grant (use Gerrit), 2017/02/15 22:03:13]

Changing headers broke compilation of this file which does require UsbDeviceImpl
to be defined.

+
 class UsbServiceImpl :
 #if defined(OS_WIN)
     public DeviceMonitorWin::Observer,
 #endif  // OS_WIN
     public UsbService {
  public:
   explicit UsbServiceImpl(
       scoped_refptr<base::SequencedTaskRunner> blocking_task_runner);
   ~UsbServiceImpl() override;
 
@@ skipping 69 matching lines @@
 #if defined(OS_WIN)
   ScopedObserver<DeviceMonitorWin, DeviceMonitorWin::Observer> device_observer_;
 #endif  // OS_WIN
 
   base::WeakPtrFactory<UsbServiceImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(UsbServiceImpl);
 };
 
 }  // namespace device