Update device/usb and its Mojo interface for variable size ISO packets.

device/devices_app/usb/type_converters.cc

Index: device/devices_app/usb/type_converters.cc
diff --git a/device/devices_app/usb/type_converters.cc b/device/devices_app/usb/type_converters.cc
index cadf9cf9274aef15b7c9c094fb4bb35c773794d0..c910cd619f809552eb126f023ad3ce725ad494c8 100644
--- a/device/devices_app/usb/type_converters.cc
+++ b/device/devices_app/usb/type_converters.cc
@@ -267,4 +267,17 @@ TypeConverter<device::usb::DeviceInfoPtr, device::UsbDevice>::Convert(
   return info;
 }
 
+// static
+device::usb::IsochronousPacketPtr
+TypeConverter<device::usb::IsochronousPacketPtr,
+              device::UsbDeviceHandle::IsochronousPacket>::
+    Convert(const device::UsbDeviceHandle::IsochronousPacket& packet) {
+  device::usb::IsochronousPacketPtr info =
+      device::usb::IsochronousPacket::New();
+  info->length = packet.length;
+  info->transferred_length = packet.transferred_length;
+  info->status = mojo::ConvertTo<device::usb::TransferStatus>(packet.status);
+  return info;
+}
+
 }  // namespace mojo