Add WebUSB bindings and client interface

Source/modules/webusb/USBInterface.h

Index: Source/modules/webusb/USBInterface.h
diff --git a/Source/modules/webusb/USBInterface.h b/Source/modules/webusb/USBInterface.h
new file mode 100644
index 0000000000000000000000000000000000000000..75c366577fccc01c3644c945a75e64bb18bc25a8
--- /dev/null
+++ b/Source/modules/webusb/USBInterface.h
@@ -0,0 +1,42 @@
+// 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 USBInterface_h
+#define USBInterface_h
+
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "platform/heap/Heap.h"
+#include "public/platform/modules/webusb/WebUSBDeviceInfo.h"
+
+namespace blink {
+
+class ExceptionState;
+class USBAlternateInterface;
+class USBConfiguration;
+
+class USBInterface
+    : public GarbageCollected<USBInterface>
+    , public ScriptWrappable {
+    DEFINE_WRAPPERTYPEINFO();
+public:
+    static USBInterface* create(const USBConfiguration*, size_t interfaceIndex);
+    static USBInterface* create(const USBConfiguration*, size_t interfaceIndex, ExceptionState&);
+
+    USBInterface(const USBConfiguration*, size_t interfaceIndex);
+
+    const WebUSBDeviceInfo::Interface& info() const;
+
+    uint8_t interfaceNumber() const;
+    HeapVector<Member<USBAlternateInterface>> alternates() const;
+
+    DECLARE_TRACE();
+
+private:
+    Member<const USBConfiguration> m_configuration;
+    size_t m_interfaceIndex;
+};
+
+} // namespace blink
+
+#endif // USBInterface_h