Implement basic USB setup in the cups printer detector. Factor out

chrome/browser/chromeos/printing/usb_util.h

+// Copyright 2017 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.
+
+// Utility routines for working with UsbDevices that are printers.
+
+#ifndef CHROME_BROWSER_CHROMEOS_PRINTING_USB_UTIL_H__
+#define CHROME_BROWSER_CHROMEOS_PRINTING_USB_UTIL_H__
+
+#include <string>
+
+#include "base/logging.h"

[tbarzic, 2017/03/14 01:43:33]

can you remove includes you don't need here?

[Carlson, 2017/03/15 00:31:16]

Done.

+#include "base/memory/ref_counted.h"
+#include "base/strings/stringprintf.h"
+#include "base/strings/utf_string_conversions.h"
+#include "chromeos/printing/printer_configuration.h"
+#include "device/usb/usb_device.h"
+

[tbarzic, 2017/03/14 01:43:32]

forward declare Printer and  UsbDevice?

[Carlson, 2017/03/15 00:31:16]

I didn't realize until today that the rules about this are different for Google
Style Guide, and Chromium.  Thanks.

+namespace chromeos {
+
+bool UsbDeviceIsPrinter(scoped_refptr<device::UsbDevice> usb_device);
+
+// Convert the interesting details of a device to a string, for
+// logging/debugging.
+std::string UsbPrinterDeviceDetailsAsString(const device::UsbDevice& device);
+
+// Attempt to gather all the information we need to work with this printer by
+// querying the USB device.  This should only be called using devices we believe
+// are printers, not arbitrary USB devices, as we may get weird partial results
+// from arbitrary devices.
+//
+// Returns true on success.  On false, printer may have partial results.
+bool UsbDeviceToPrinter(const device::UsbDevice& device,
+                        chromeos::Printer* printer);
+
+}  // namespace chromeos
+#endif  // CHROME_BROWSER_CHROMEOS_PRINTING_USB_UTIL_H__