Add WebUSB bindings and client interface

Source/modules/webusb/USBEndpoint.h

+// 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 USBEndpoint_h
+#define USBEndpoint_h
+
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "platform/heap/Heap.h"
+#include "public/platform/modules/webusb/WebUSBDeviceInfo.h"
+
+namespace blink {
+
+class USBAlternateInterface;
+
+class USBEndpoint
+    : public GarbageCollected<USBEndpoint>
+    , public ScriptWrappable {
+    DEFINE_WRAPPERTYPEINFO();
+public:
+    static USBEndpoint* create(const USBAlternateInterface*, size_t endpointIndex);
+
+    USBEndpoint(const USBAlternateInterface*, size_t endpointIndex);
+
+    const WebUSBDeviceInfo::Endpoint& info() const;
+
+    uint8_t endpointNumber() const;
+    String direction() const;
+    String type() const;
+    unsigned packetSize() const;
+
+    DECLARE_TRACE();
+
+private:
+    Member<const USBAlternateInterface> m_alternate;
+    size_t m_endpointIndex;
+};
+
+} // namespace blink
+
+#endif // USBEndpoint_h