Add WebUSB bindings and client interface

Source/modules/webusb/USBConfiguration.cpp

+// 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 "config.h"
+#include "modules/webusb/USBConfiguration.h"
+
+#include "modules/webusb/USBDevice.h"
+#include "modules/webusb/USBInterface.h"
+
+namespace blink {
+
+// static
+USBConfiguration* USBConfiguration::create(const USBDevice* device, size_t configurationIndex)
+{
+    return new USBConfiguration(device, configurationIndex);
+}
+
+USBConfiguration::USBConfiguration(const USBDevice* device, size_t configurationIndex)
+    : m_device(device)
+    , m_configurationIndex(configurationIndex)
+{
+}
+
+const WebUSBDeviceInfo::Configuration& USBConfiguration::info() const
+{
+    const WebUSBDeviceInfo& deviceInfo = m_device->info();
+    ASSERT(m_configurationIndex < deviceInfo.configurations.size());
+    return deviceInfo.configurations[m_configurationIndex];
+}
+
+uint8_t USBConfiguration::configurationValue() const
+{
+    return info().configurationValue;
+}
+
+String USBConfiguration::configurationName() const
+{
+    return info().configurationName;
+}
+
+HeapVector<Member<USBInterface>> USBConfiguration::interfaces() const
+{
+    HeapVector<Member<USBInterface>> interfaces;
+    for (size_t i = 0; i < info().interfaces.size(); ++i)
+        interfaces.append(USBInterface::create(this, i));
+    return interfaces;
+}
+
+DEFINE_TRACE(USBConfiguration)
+{
+    visitor->trace(m_device);
+}
+
+} // namespace blink