Store devices that only need to be enumerated once

device/usb/usb_service_impl.h

Index: device/usb/usb_service_impl.h
diff --git a/device/usb/usb_service_impl.h b/device/usb/usb_service_impl.h
index 7b05904cbac81f618da378f1a76e98d450df366d..203aab411afa217baeeabd7288464255abf29588 100644
--- a/device/usb/usb_service_impl.h
+++ b/device/usb/usb_service_impl.h
@@ -80,6 +80,11 @@ class UsbServiceImpl :
   void OnPlatformDeviceAdded(PlatformUsbDevice platform_device);
   void OnPlatformDeviceRemoved(PlatformUsbDevice platform_device);
 
+  // Add |platform_device| to the |ignored_devices_| and
+  // run |refresh_complete|.
+  void EnumerationFailed(PlatformUsbDevice platform_device,
+                         const base::Closure& refresh_complete);
+
   scoped_refptr<UsbContext> context_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   scoped_refptr<base::SequencedTaskRunner> blocking_task_runner_;
@@ -105,6 +110,10 @@ class UsbServiceImpl :
       PlatformDeviceMap;
   PlatformDeviceMap platform_devices_;
 
+  // The set of devices that only need to be enumerated once and then can be
+  // ignored (for example, hub devices, devices that failed enumeration, etc.).
+  std::set<PlatformUsbDevice> ignored_devices_;
+
   // Tracks PlatformUsbDevices that might be removed while they are being
   // enumerated.
   std::set<PlatformUsbDevice> devices_being_enumerated_;