Add utilities to parse WebUSB device descriptors.

device/usb/webusb_descriptors.h

Index: device/usb/webusb_descriptors.h
diff --git a/device/usb/webusb_descriptors.h b/device/usb/webusb_descriptors.h
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index 0000000000000000000000000000000000000000..696d02489611da3ddb6424e7a6405b6ca166e136
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+++ b/device/usb/webusb_descriptors.h
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+// 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.
+
+#ifndef DEVICE_USB_WEBUSB_DESCRIPTORS_H_
+#define DEVICE_USB_WEBUSB_DESCRIPTORS_H_
+
+#include <stdint.h>
+#include <vector>
+
+#include "url/gurl.h"
+
+namespace device {
+
+struct WebUsbFunctionSubset {
+  WebUsbFunctionSubset();
+  ~WebUsbFunctionSubset();
+
+  uint8_t first_interface;
+  std::vector<GURL> origins;
+};
+
+struct WebUsbConfigurationSubset {
+  WebUsbConfigurationSubset();
+  ~WebUsbConfigurationSubset();
+
+  uint8_t configuration_value;
+  std::vector<GURL> origins;
+  std::vector<WebUsbFunctionSubset> functions;
+};
+
+struct WebUsbDescriptorSet {
+  WebUsbDescriptorSet();
+  ~WebUsbDescriptorSet();
+
+  bool Parse(const std::vector<uint8_t>& bytes);
+
+  std::vector<GURL> origins;
+  std::vector<WebUsbConfigurationSubset> configurations;
+};
+
+struct WebUsbPlatformCapabilityDescriptor {
+  WebUsbPlatformCapabilityDescriptor();
+  ~WebUsbPlatformCapabilityDescriptor();
+
+  bool ParseFromBosDescriptor(const std::vector<uint8_t>& bytes);
+
+  uint16_t version;
+  uint8_t vendor_code;
+};
+
+}  // device
+
+#endif  // DEVICE_USB_WEBUSB_DESCRIPTORS_H_